Wednesday, April 27, 2011
Monday, April 25, 2011
关于毅力的名言
1．世人缺乏的是毅力，而非气力。——雨果
2．艺术的大道上荆棘丛生，这也是好事，常人都望而怯步，只有意志坚强的人例外。——雨果
3．向着某一天终于要达到的那个终极目标迈步还不够，还要把每一步骤看成目标，使它作为步骤而起作用。 ——歌德
4．取得成就时坚持不懈，要比遭到失败时顽强不屈更重要。 ——拉罗什夫科，法国作家
5．忍耐和坚持虽是痛苦的事情，但却能渐渐地为你带来好处。 ——奥维德，古罗马诗人
6．无论什么时候，不管遇到什么情况，我绝不允许自己有一点点灰心丧气。 ——爱 迪 生
7．锲而舍之，朽木不折；锲而不舍，金石可镂。 —— 荀 况
8．古今之成大事业、大学问者，必经过三种之境界：“昨夜西风凋碧树，独上高楼，望尽天涯路”，此第一境界也；“衣带渐宽终不悔，为伊消得人憔悴”，此第二境界也；“众里寻他千百度，蓦然回首，那人却在灯火阑珊处”，此第三境界也。 ——王 国 维
9．一个人做事，在动手之前，当然要详慎考虑；但是计划或方针已定之后，就要认定目标前进，不可再有迟疑不决的态度，这就是坚毅的态度。 ——邹 韬 奋
10．我们应有恒心，尤其要有自信心！我们必须相信，我们的天赋是要用来做某种事情的。 ——居里 夫人
11．一个人只要强烈地坚持不懈地追求，他就能达到目的。——司汤达
12．下苦功，三个字，一个叫下，一个叫苦，一个叫功，一定要振作精神，下苦功。——毛泽东
13．只要持之以恒，知识丰富了，终能发现其奥秘。——杨振宁
14．伟大变为可笑只有一步，但再走一步，可笑又会变为伟大。——佩思
15．重复是学习之母。——狄慈根
16．涓滴之水终可以磨损大石，不是由于它力量强大，而是由于昼夜不舍的滴坠。——贝多芬
17．读不在三更五鼓，功只怕一曝十寒。——郭沫若
18．为学犹掘井，井愈深土愈难出，若不决心到底，岂得见泉源乎？——张九功
19．为学须刚与恒，不刚则隋隳，不恒则退。——冯子咸
20．进锐退速。——孟珂《孟子》
21．学而时习之，不亦说乎？——孔丘《论语·学而》
22．欲速而不达。——孔丘《论语》
23．日日行，不怕千万里；常常做，不怕千万事。——金樱《格言联壁》
24．骐骥一跃，不能十步；驽马十驾，功在不舍。（《荀子·劝学》）
25．贵有恒，何必三更起五更眠。最无益，只怕一日曝十日寒。——毛泽东
27．伟大的事业是根源于坚韧不断地工作，以全副精神去从事，不避艰苦。——罗 素
28．顽强的毅力可以征服世界上任何一座高峰。——狄更斯
29．有毅力的人，能从磐石里挤出水满。——谚 语
30．一朝开始便永远能够将事业续继下去的人是幸福的。——赫尔克
31．毅力是永久的享受。——布莱克
32．惟坚韧者始能遂其志。——富兰克林
33．忍耐虽然痛苦，果实却最香甜。——萨 迪
34．所有坚韧不拔的努力迟早会取得报酬的。——安格尔
35．耐心和持久胜于激烈的狂热。——拉封丹
36．人的思想是了不起的，只要专注于某一项事业，就一定会做出使自己感到吃惊的成绩来。——马克·吐温
36．人们的毅力是衡量决心的尺度。——穆泰奈比
38．成大事不在于力量的大小，而在于能坚持多久。——约翰生
39．伟大的毅力只为伟大的目的而产生。 ——斯大林
40．人要有毅力，否则将一事无成。 ——居里 夫人
41．只有毅力才能使我们成功。而毅力是来源于毫不动摇，坚决采取为达到成功而需要的手段。——车尔尼雪夫斯基
42．达到目的有两个途径，即势力与毅力，势力只为少数人所有，但坚忍不拔的毅力却是多数人都有的，它的沉默力量往往可随时达到无可抵抗的地步。 ——拿破仑
43．阻碍弱者前进路上的花岗石，会成为强者前进路上的垫脚石。 ——卡莱尔
44．谚云：世上无难事，只畏有心人，有心之人，即立志之坚者也，志坚则不畏事之不成。——任弼时
45．是使自己的人格伟大还是渺小呢？这完全仰仗这个人自己的意志。 ——席勒
46．天下无难事，惟坚忍二字，为成功之要诀。 ——黄兴
47．要在文化上有成绩，则非韧不可。 ——鲁迅
48．宿命论是那些缺乏意志力的弱者的借口。——罗曼·罗兰
49．天才是永恒的耐心。——米开朗琪罗
50．伟大的人做事决不半途而废。 ——汉密尔顿
51．坚强者能在命运风暴中奋斗。——爱迪生
52．伟大的事业需要始终不渝的精神。——伏尔泰
53．告诉你使我达到成功的奥秘吧，我惟一的力量就是我的坚持精神。——巴斯德
54．伟大人物的最明显标志，就是他坚强的意志，不管环境变换到何种地步，他的初衷与希望仍不会有丝毫的改变，而终于克服障碍，以达到期望的目的。——爱迪生
55．顽强的毅力可以征服世界上任何一座高峰。——狄更斯
56．在科学上面是没有平坦的大路可走的，只有那在崎岖小路的攀登上不畏劳苦的人，才有希望到达光辉的顶点。——马克思
57．哪有斩不断的荆棘？哪有打不死的豺虎？哪有推不翻的山岳？你只须奋斗着，猛勇地奋斗着；持续着，永远的持续着，胜利就是你的了。——邓中夏
58．就是有九十九个困难，只要有一个坚强的意志就不困难。——杨根思
59．困难只能吓倒懦夫懒汉，而胜利永远属于敢于攀登科学高峰的人。——茅以升
60．即使慢，驰而不息，纵会落后，纵会失败，但一定可以达到他所向的目标。——鲁迅
61．我每看运动会时，常常这样想：优胜者固然可敬，但那虽然落后而仍非跑至终点不止的竞技者，和见了这样竞技者而肃然不笑的看客，乃正是中国将来的脊梁。——鲁迅
62．百丈之台，其始则一石耳，由是而二石焉，由是而三石，四石以至于千万石焉。学习亦然。今日记一事，明日悟一理，积久而成学。——毛泽东
63．咬住青山不放松，立根原在破岩中；千磨万击还坚劲，任尔东西南北风。——郑板桥
64．胜利属于最坚忍的人。——拿破仑
66．胜利的道路是迂回曲折的。象山间小径一样，这条路有时先折回来，然后伸向前去；象山
Saturday, April 23, 2011
Chinese Organization around Campus
www.acpdfw.org
Association of Chinese Professionals Foundation, Dallas /Fort-Worth
http://www.cie-dfw.org/
Chinese Institute of Engineers
Association of Chinese Professionals Foundation, Dallas /Fort-Worth
http://www.cie-dfw.org/
Chinese Institute of Engineers
Friday, April 22, 2011
Automatic Speech Recognition:
Automatic Speech Recognition:
On-line Courses and Educational Material Relevant to Speech Recognition
Thursday, April 21, 2011
Wednesday, April 20, 2011
Lesson 44 Patterns of Culture
The study of custom can be profitable only after certain preliminary propositions have been accepted, and some of them have been violently violated.In the first place, any scientific study requires that there be no preferential weighting of one or another of the items in the series it selects for its consideration.
Matlab Audio Processing Examples
Matlab Audio Processing Examples
Introduction
This area contains several little pieces of Matlab code that might be fun or useful to play with.- Robust landmark-based audio fingerprinting This is my implementation of the music audio fingerprinting scheme invented by Avery Wang for Shazam. It is able to match short and noisy excerpts of music against a reference database. The database part is a bit vestigial in Matlab, but the landmark hashing works pretty well.
- Aligning MIDI scores to music audio - It can be very useful to take a MIDI piece that closely matches the notes in a real performance, then make a precise temporal alignment between the two; this allows the discrete MIDI description to be treated as an approximate transcript of the audio. This code performs this alignment, based on the approach of constructing an approximate, schematic version of the expected spectrogram from the MIDI notes.
- Chroma Features Analysis and Synthesis - Chroma features capture the melodic/harmonic signature of spectra, and form a nice musical complement to more common spectral features such as MFCCs. This package includes a few different ways to calculate them, as well as a resynthesis routine that modulates "Shepard tones" to resynthesize audio with the chromatic content defined by the features.
- Beat Tracking and Music Matching - an easy-to-use beat tracker in Matlab, plus code for describing music audio as per-beat chroma features, which is an effective representation for matching songs that have the same melodic/harmonic content despite changes in tempo or instrumentation.
- Constant-Q (Log-Frequency) Spectrogram - an equivalent for Matlab's short-time Fourier transform calculation/display routine specgram() that instead uses a log-frequency axis, so that an octave (doubling in frequency) corresponds to a constant number of bins, regardless of absolute frequency. This projection is particularly useful in music processing, since musical transposition corresponds only to translation. Also includes a drop-in replacement for specgram() (for people without the signal processing toolbox).
- Gammmatone (auditory) Spectrogram - another specgram()-like function, this time for calculating time-frequency surfaces based on the gammatone approximations to auditory filters.
- Time-domain audio scrambling - removes some of the identifiability of audio signals by shuffling overlapping time windows.
- RASTA/PLP/MFCC feature calculation and inversion - a Matlab implementation of popular speech recognition feature extraction including MFCC and PLP (as defined by Hermansky and Morgan), as well as code to map features back to (noise-excited) audio. Includes a page on Reproducing the feature outputs of common programs.
- mp3read and mp3write - a wrapper to read MPEG-Audio layer III (MP3) files into Matlab that behaves like wavread(), and another one to write MP3 files that behaves like wavwrite().
- m4aread - a wrapper to use "faad" to read MPEG4 Audio (AAC / M4A) files into Matlab, just like wavread() and mp3read() above.
- popen for Matlab - source code for Mex extensions that allow access to the Unix popen() function to create processes that provide or accept long streams of data one bit at a time. The neat version of mp3write uses this, but it's only available on Unix (Linux, Mac OS X, etc.).
- Dynamic Time Warp - A simple implementation of dynamic programming to align the STFTs of two 'similar' sound examples, then use the Phase Vocoder to warp the timebase of one to match the other.
- Phase vocoder - an implementation of the popular computer music algorithm for arbitrarily altering the time base of a sound without changing is short-time spectral character.
- SOLAFS - an implementation of the popular speech processing algorithm for changing the timescale of speech by deleting or duplicating entire pitch cycles.
- Sinewave Speech Analysis/Synthesis - code to resynthesize sinewave speech samples from the example parameter files made available at the Haskins site.
2001-03-12 Update:Sinewave parameter analysis, based on simple LPC pole fitting, is now available!. (Pure LPC analysis/synthesis is included as a bonus!) - Spectral warping of LPC models - a warping transformation applied to LPC-extracted vocal tract resonance model can change the apparent 'size' of the speaker.
- Plucked String Synthesis - a simple example of the digital waveguide synthesis of musical instruments developed at Stanford's CCRMA.
- Sinewave (Harmonic) Modeling - a simple implementation of sinusoid modeling based on picking peaks in the short-time Fourier transform magnitude. (Also known as harmonic modeling or McAulay-Quatieri modeling). Includes some provision for LPC modeling of noisy residual, along the lines of Harmonic+Noise modeling, or Serra's Spectral Modeling Synthesis (SMS).
- Time-frequency automatic gain control - takes an audio waveform, and adjusts its gain (in time and frequency) to approach a constant energy level.
Acknowledgment
This material is based in part upon work supported by the National Science Foundation under Grant No. IIS-0238301. Any opinions, findings and conclusions or recomendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation (NSF).How to: Compile a Native C++ Program from the Command Line
To create a Visual C++ source file and compile it on the command line
Open the Visual Studio 2005 Command Prompt window.
Click the Start button, then point to All Programs, Microsoft Visual Studio 2005, Visual Studio Tools, and click Visual Studio 2005 Command Prompt.
Note
The Visual Studio 2005 Command Prompt automatically sets up the correct path to the Visual C++ compiler and any needed libraries, so it is used instead of the regular Command Prompt window. For more information, see Setting the Path and Environment Variables for Command-Line Builds.
At the command prompt, type notepad simple.cpp and press Enter.
Click Yes when prompted to create a new file.
In Notepad, type the following lines:
#include
int main()
{
std::cout << "This is a native C++ program." << std::endl;
return 0;
}
On the File menu, click Save. You have created a Visual C++ source file.
On the File menu, click Exit to close Notepad.
At the command line prompt, type cl /EHsc simple.cpp
Open the Visual Studio 2005 Command Prompt window.
Click the Start button, then point to All Programs, Microsoft Visual Studio 2005, Visual Studio Tools, and click Visual Studio 2005 Command Prompt.
Note
The Visual Studio 2005 Command Prompt automatically sets up the correct path to the Visual C++ compiler and any needed libraries, so it is used instead of the regular Command Prompt window. For more information, see Setting the Path and Environment Variables for Command-Line Builds.
At the command prompt, type notepad simple.cpp and press Enter.
Click Yes when prompted to create a new file.
In Notepad, type the following lines:
#include
int main()
{
std::cout << "This is a native C++ program." << std::endl;
return 0;
}
On the File menu, click Save. You have created a Visual C++ source file.
On the File menu, click Exit to close Notepad.
At the command line prompt, type cl /EHsc simple.cpp
Friday, April 15, 2011
Microsoft Internship Interview 2011 (Hyderabad Revisited) | using namespace LIFE;
Finally I get a couple of minutes to blog about my recent interview at Microsoft for the position of a summer intern. Microsoft came to our college campus and conducted a written test. I performed well enough to be selected for the on-site interview and was invited to Microsoft’s Hyderabad campus along with a couple of other batchmates. I will just mention the good questions which were asked during the interview/written test to me and others.
The written test was pretty simple. The only objective question that can be called challenging was related to Semaphores. But if you know the concept, you are good to go.
There were 5 subjective questions. One output problem (very easy), one question that was cancelled (lol), one question for test cases (pretty simple), one algorithm and one design question. I’ll only be listing the moderately difficult questions here along with little hints.
The algorithm related question was as follows : (don’t remember the exact words, but this is the essence)
Q: We have a sorted shifted array,i.e., an array initially sorted in ascending/descending order and then rotated by a certain amount (lets say k). We don’t know which direction the array has been rotated in. What you are supposed to do is find an element in the array.
Hint : Everyone can do it in O(n) time. Think about the search algorithm that gives O(lg n) and try and modify it.
The design question was also pretty simple. Here it is :
Q : Design a system for a hospital for the staff to get details about the patients.
Concepts to remember : Object Oriented Programming, Databases (Views, ER Models, Schemas, etc), Artificial Intelligence (Speech recognition, NLP), Algorithm Design (for searching, sorting, etc.)
These were the questions for the written test. Answering most of them correctly, I earned a free trip to Hyderabad. Better still, I got to see the aw-f-some campus of Microsoft in Hyderabad. Table tennis tables, no formal clothes required, coffee and comfortable chairs everywhere – now that is what I call work environment!
Since the post is interview oriented, I won’t go into the details of my trip (although I want to…so badly!) Let me directly come to the questions asked and my hints
Q : You have been given an inorder expression and a preorder expression. Now get the postorder expression from the same.
Hint : Trees
Q : Write a program to reverse a string and its test cases.
Hint : D-uh! You really want a hint for this?
Q : There is an array with every element having a duplicate except one element. How will you find the number without a duplicate?
Hint : Are you thinking about O(n lg n) ? That is simple. Think about O(n). Try and use XOR.
Q : Let us modify the above question. Now there are two such elements which do not have a duplicate. Find them.
Hint : Use XOR. Try to separate the two numbers into 2 different arrays. Then apply the same solution you did above.
Q : Write a program to add numbers stored in 2 linked lists, i.e., if one number is 367, the first node has 3, the next 6 and the next 7. So you have to add two such numbers. Write test cases for your program.
Hint : Basic traversal and corresponding addition after reversing the linked lists. Take care of memory issues.
These were the questions that I was asked. Although I was hoping they would ask me about my projects, none of my interviewers asked me about them and instead focused on coding. No sweat.
Let me now list some other questions that my friends were asked in their interviews.
Q : How will you reverse a linked list (use recursion)?
Hint : Store the current node’s position in a pointer, call the function again, and after that exchange the link. Hope you get what I mean. Otherwise, leave a comment.
Q : Is there a difference between a null string and an empty string?
Hint : Think in terms of memory.
Q : Write a program for string concatenation and its test cases.
Hint : Be careful to give test cases from the user’s point of view.
These are all the questions I remember at the moment.
Oh! And did I forget to mention, the interview process is not over yet. I still have to face one phone interview (you can read about my phone interview here) before the final decision will be made! Let us keep our fingers crossed! Hoping to clear the last round too \m/
The written test was pretty simple. The only objective question that can be called challenging was related to Semaphores. But if you know the concept, you are good to go.
There were 5 subjective questions. One output problem (very easy), one question that was cancelled (lol), one question for test cases (pretty simple), one algorithm and one design question. I’ll only be listing the moderately difficult questions here along with little hints.
The algorithm related question was as follows : (don’t remember the exact words, but this is the essence)
Q: We have a sorted shifted array,i.e., an array initially sorted in ascending/descending order and then rotated by a certain amount (lets say k). We don’t know which direction the array has been rotated in. What you are supposed to do is find an element in the array.
Hint : Everyone can do it in O(n) time. Think about the search algorithm that gives O(lg n) and try and modify it.
The design question was also pretty simple. Here it is :
Q : Design a system for a hospital for the staff to get details about the patients.
Concepts to remember : Object Oriented Programming, Databases (Views, ER Models, Schemas, etc), Artificial Intelligence (Speech recognition, NLP), Algorithm Design (for searching, sorting, etc.)
These were the questions for the written test. Answering most of them correctly, I earned a free trip to Hyderabad. Better still, I got to see the aw-f-some campus of Microsoft in Hyderabad. Table tennis tables, no formal clothes required, coffee and comfortable chairs everywhere – now that is what I call work environment!
Since the post is interview oriented, I won’t go into the details of my trip (although I want to…so badly!) Let me directly come to the questions asked and my hints
Q : You have been given an inorder expression and a preorder expression. Now get the postorder expression from the same.
Hint : Trees
Q : Write a program to reverse a string and its test cases.
Hint : D-uh! You really want a hint for this?
Q : There is an array with every element having a duplicate except one element. How will you find the number without a duplicate?
Hint : Are you thinking about O(n lg n) ? That is simple. Think about O(n). Try and use XOR.
Q : Let us modify the above question. Now there are two such elements which do not have a duplicate. Find them.
Hint : Use XOR. Try to separate the two numbers into 2 different arrays. Then apply the same solution you did above.
Q : Write a program to add numbers stored in 2 linked lists, i.e., if one number is 367, the first node has 3, the next 6 and the next 7. So you have to add two such numbers. Write test cases for your program.
Hint : Basic traversal and corresponding addition after reversing the linked lists. Take care of memory issues.
These were the questions that I was asked. Although I was hoping they would ask me about my projects, none of my interviewers asked me about them and instead focused on coding. No sweat.
Let me now list some other questions that my friends were asked in their interviews.
Q : How will you reverse a linked list (use recursion)?
Hint : Store the current node’s position in a pointer, call the function again, and after that exchange the link. Hope you get what I mean. Otherwise, leave a comment.
Q : Is there a difference between a null string and an empty string?
Hint : Think in terms of memory.
Q : Write a program for string concatenation and its test cases.
Hint : Be careful to give test cases from the user’s point of view.
These are all the questions I remember at the moment.
Oh! And did I forget to mention, the interview process is not over yet. I still have to face one phone interview (you can read about my phone interview here) before the final decision will be made! Let us keep our fingers crossed! Hoping to clear the last round too \m/
Interview Questions - Microsoft, etc.
Interview Questions - Microsoft, etc.
Disclaimer: This page is in no way connected with Microsoft Corporation, its affiliates, friends or haters
This page is moving to http://www.softwareinterview.com. Please update your bookmarks.
What?
Here is a set of questions that I have with me which software guys have asked at interviews in the past, most of them are actually from Microsoft but a few have been pulled together from other places too. I have collected these from friends and would welcome any additions from you. Mail them to kiran AT usc DOT edu. Do send me your solutions, but the intent of this page is to kindle enough interest in you to try similar logic and programming questions.
PLEASE DO NOT REQUEST ME FOR MORE SOLUTIONS!
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Why?
I have grown up reading Martin Gardner's Scientific American columns on Mathematical Games and interesting mathematics olympiad problems in high school. I discovered, to my delight, Bentley's Programming Pearls and David Gries' The Science of Programming in my computer science education. There is underlying beauty in mathematics and computer science. Some find it and others hate the subjects. When I found some of the Microsoft interview questions in graduate school, they were similar to mathematical puzzles that I was interested in. I started collecting them more as an illustration of interesting logic puzzles and algorithms in programming, than as an interview aid. If it has morphed into an interview questions page, that is more due to interest from all interviewees out there.
Some of the programming questions have a basic foundation in mathematics and algorithms. If the given data structure has a specific amount of information and the question asks you to extract/modify the given information, it is possible (though not always obvious) to find optimal solutions, and prove that it cannot be done any better, by quantifying the information content. But, there are always elegant and ugly ways to extract the same information. When you manage to find out the optimal solution to a problem, it usually not only turns out to be elegant, but also has the "aha!" factor to it. Try proving on paper the following question from my undergraduate mid-term:
1. Everyone Loves All Lovers
2. Romeo Loves Juliet
Therefore, prove (i.e. 1 AND 2 => 3)
3. I Love You
How?
To answer one of the more frequent questions that I get: No! I have never interviewed at Microsoft. In fact, I work in a microprocessor company far removed from any software development (though I work mostly in programming). However, I have had two of my roommates and two more housemates eventually working in Microsoft, in addition to a large number of friends. None of them have contributed to this page AFTER they started working at Microsoft. Microsoft itself does not hold any patents and nor has it invented most of the questions. Most of them come from mathematics and physics books, party puzzles, programming lore and standard textbooks. I know many companies ask similar questions, though Microsoft might have made the practice more common (especially with the manhole cover type of questions).
Usage
I have spent some time in collecting with the intention of their value as a practice session. They are not meant to be exact questions that you need to know and answer in an interview. They are supposed to make you think! Discuss with your friends, colleagues, professors for answers (get your tuition money's worth). I have left the page in simple text format so you can print them out and try them on your flight to the interview in case you are pressed for time. One of the strangest phone calls I remember is from a girl, staying up in a Microsoft provided hotel room in Redmond the night before the interview, asking me about the solution for one of the questions from this page. I hope the rest of you are saner (or do not have my phone number).
Kiran Bondalapati Ze Meat
Puzzles, Riddles, etc.
Programming Questions
Computer Networks, Databases, etc.
Computer Architecture
Puzzles, Riddles and Others
0. Classic: If a bear walks one mile south, turns left and walks one mile to the east and then turns left again and walks one mile north and arrives at its original position, what is the color of the bear.
ANS. The color of the bear is trivial. The possible solutions to it are interesting. In addition to the trivial north pole, there are additional circles near south pole. Think it out.
* 1. Given a rectangular (cuboidal for the puritans) cake with a rectangular piece removed (any size or orientation), how would you cut the remainder of the cake into two equal halves with one straight cut of a knife?
ANS. Join the centers of the original and the removed rectangle. It works for cuboids too! BTW, I have been getting many questions asking why a horizontal slice across the middle will not do. Please note the "any size or orientation" in the question! Don't get boxed in by the way you cut your birthday cake :) Think out of the box.
2. There are 3 baskets. one of them have apples, one has oranges only and the other has mixture of apples and oranges. The labels on their baskets always lie. (i.e. if the label says oranges, you are sure that it doesn't have oranges only,it could be a mixture) The task is to pick one basket and pick only one fruit from it and then correctly label all the three baskets.
HINT. There are only two combinations of distributions in which ALL the baskets have wrong labels. By picking a fruit from the one labeled MIXTURE, it is possible to tell what the other two baskets have.
3. You have 8 balls. One of them is defective and weighs less than others. You have a balance to measure balls against each other. In 2 weighings how do you find the defective one?
4. Why is a manhole cover round?
HINT. The diagonal of a square hole is larger than the side of a cover!
Alternate answers: 1. Round covers can be transported by one person, because they can be rolled on their edge. 2. A round cover doesn't need to be rotated to fit over a hole.
5. How many cars are there in the USA?
6. You've got someone working for you for seven days and a gold bar to pay them. The gold bar is segmented into seven connected pieces. You must give them a piece of gold at the end of every day. If you are only allowed to make two breaks in the gold bar, how do you pay your worker?
7. One train leaves Los Angeles at 15mph heading for New York. Another train leaves from New York at 20mph heading for Los Angeles on the same track. If a bird, flying at 25mph, leaves from Los Angeles at the same time as the train and flies back and forth between the two trains until they collide, how far will the bird have traveled?
HINT. Think relative speed of the trains.
8. You have two jars, 50 red marbles and 50 blue marbles. A jar will be picked at random, and then a marble will be picked from the jar. Placing all of the marbles in the jars, how can you maximize the chances of a red marble being picked? What are the exact odds of getting a red marble using your scheme?
9. Imagine you are standing in front of a mirror, facing it. Raise your left hand. Raise your right hand. Look at your reflection. When you raise your left hand your reflection raises what appears to be his right hand. But when you tilt your head up, your reflection does too, and does not appear to tilt his/her head down. Why is it that the mirror appears to reverse left and right, but not up and down?
10. You have 5 jars of pills. Each pill weighs 10 gram, except for contaminated pills contained in one jar, where each pill weighs 9 gm. Given a scale, how could you tell which jar had the contaminated pills in just one measurement?
ANS. 1. Mark the jars with numbers 1, 2, 3, 4, and 5.
2. Take 1 pill from jar 1, take 2 pills from jar 2, take 3 pills from jar 3, take 4 pills from jar 4 and take 5 pills from jar 5.
3. Put all of them on the scale at once and take the measurement.
4. Now, subtract the measurement from 150 ( 1*10 + 2*10 + 3*10 + 4*10 + 5*10)
5. The result will give you the jar number which has contaminated pill.
11. If you had an infinite supply of water and a 5 quart and 3 quart pail, how would you measure exactly 4 quarts?
12. You have a bucket of jelly beans. Some are red, some are blue, and some green. With your eyes closed, pick out 2 of a like color. How many do you have to grab to be sure you have 2 of the same?
13. Which way should the key turn in a car door to unlock it?
14. If you could remove any of the 50 states, which state would it be and why?
15. There are four dogs/ants/people at four corners of a square of unit distance. At the same instant all of them start running with unit speed towards the person on their clockwise direction and will always run towards that target. How long does it take for them to meet and where?
HINT. They will meet in the center and the distance covered by them is independent of the path they actually take (a spiral).
16. (from Tara Hovel) A helicopter drops two trains, each on a parachute, onto a straight infinite railway line. There is an undefined distance between the two trains. Each faces the same direction, and upon landing, the parachute attached to each train falls to the ground next to the train and detaches. Each train has a microchip that controls its motion. The chips are identical. There is no way for the trains to know where they are. You need to write the code in the chip to make the trains bump into each other. Each line of code takes a single clock cycle to execute.
You can use the following commands (and only these);
MF - moves the train forward
MB - moves the train backward
IF (P) - conditional that's satisfied if the train is next to a parachute. There is no "then" to this IF statement.
GOTO
ANS.
A: MF
IF (P)
GOTO B
GOTO A
-----
B: MF
GOTO B
Explanation: The first line simply gets them off the parachutes. You need to get the trains off their parachutes so the back train can find the front train's parachute, creating a special condition that will allow it to break out of the code they both have to follow initially. They both loop through A: until the back train finds the front train's parachute, at which point it goes to B: and gets stuck in that loop. The front train still hasn't found a parachute, so it keeps in the A loop. Because each line of code takes a "clock cycle" to execute, it takes longer to execute the A loop than the B loop, therefore the back train (running in the B loop) will catch up to the front train.
Personality
It is best to read some website or a book for questions like these.
1. Tell me the courses you liked and why did you like them.
2. Give an instance in your life in which you were faced with a problem and you tackled it successfully.
3. What is your ideal working environment.
4. Why do you think you are smart.
5. Questions on the projects listed on the Resume.
6. Do you want to know any thing about the company.( Try to ask some relevant and interesting question).
7. How long do you want to stay in USA and why (I guess non-citizens get this)?
8. What is your geographical preference?
9. What are your expectations from the job.
Algorithms and Programming
1. Given a rectangular (cuboidal for the puritans) cake with a rectangular piece removed (any size or orientation), how would you cut the remainder of the cake into two equal halves with one straight cut of a knife ?
2. You're given an array containing both positive and negative integers and required to find the sub-array with the largest sum (O(N) a la KBL). Write a routine in C for the above.
3. Given an array of size N in which every number is between 1 and N, determine if there are any duplicates in it. You are allowed to destroy the array if you like. [ I ended up giving about 4 or 5 different solutions for this, each supposedly better than the others ].
4. Write a routine to draw a circle (x ** 2 + y ** 2 = r ** 2) without making use of any floating point computations at all. [ This one had me stuck for quite some time and I first gave a solution that did have floating point computations ].
5. Given only putchar (no sprintf, itoa, etc.) write a routine putlong that prints out an unsigned long in decimal. [ I gave the obvious solution of taking % 10 and / 10, which gives us the decimal value in reverse order. This requires an array since we need to print it out in the correct order. The interviewer wasn't too pleased and asked me to give a solution which didn't need the array ].
6. Give a one-line C expression to test whether a number is a power of 2. [No loops allowed - it's a simple test.]
7. Given an array of characters which form a sentence of words, give an efficient algorithm to reverse the order of the words (not characters) in it.
8. How many points are there on the globe where by walking one mile south, one mile east and one mile north you reach the place where you started.
9. Give a very good method to count the number of ones in a "n" (e.g. 32) bit number.
ANS. Given below are simple solutions, find a solution that does it in log (n) steps.
Iterative
function iterativecount (unsigned int n)
begin
int count=0;
while (n)
begin
count += n & 0x1 ;
n >>= 1;
end
return count;
end
Sparse Count
function sparsecount (unsigned int n)
begin
int count=0;
while (n)
begin
count++;
n &= (n-1);
end
return count ;
end
10. What are the different ways to implement a condition where the value of x can be either a 0 or a 1. Apparently the if then else solution has a jump when written out in assembly. if (x == 0) y=a else y=b There is a logical, arithmetic and a data structure solution to the above problem.
11. Reverse a linked list.
12. Insert in a sorted list
13. In a X's and 0's game (i.e. TIC TAC TOE) if you write a program for this give a fast way to generate the moves by the computer. I mean this should be the fastest way possible.
The answer is that you need to store all possible configurations of the board and the move that is associated with that. Then it boils down to just accessing the right element and getting the corresponding move for it. Do some analysis and do some more optimization in storage since otherwise it becomes infeasible to get the required storage in a DOS machine.
14. I was given two lines of assembly code which found the absolute value of a number stored in two's complement form. I had to recognize what the code was doing. Pretty simple if you know some assembly and some fundaes on number representation.
15. Give a fast way to multiply a number by 7.
16. How would go about finding out where to find a book in a library. (You don't know how exactly the books are organized beforehand).
17. Linked list manipulation.
18. Tradeoff between time spent in testing a product and getting into the market first.
19. What to test for given that there isn't enough time to test everything you want to.
20. First some definitions for this problem: a) An ASCII character is one byte long and the most significant bit in the byte is always '0'. b) A Kanji character is two bytes long. The only characteristic of a Kanji character is that in its first byte the most significant bit is '1'.
Now you are given an array of a characters (both ASCII and Kanji) and, an index into the array. The index points to the start of some character. Now you need to write a function to do a backspace (i.e. delete the character before the given index).
21. Delete an element from a doubly linked list.
22. Write a function to find the depth of a binary tree.
23. Given two strings S1 and S2. Delete from S2 all those characters which occur in S1 also and finally create a clean S2 with the relevant characters deleted.
24. Assuming that locks are the only reason due to which deadlocks can occur in a system. What would be a foolproof method of avoiding deadlocks in the system.
25. Reverse a linked list.
Ans: Possible answers -
iterative loop
curr->next = prev;
prev = curr;
curr = next;
next = curr->next
endloop
recursive reverse(ptr)
if (ptr->next == NULL)
return ptr;
temp = reverse(ptr->next);
temp->next = ptr;
return ptr;
end
26. Write a small lexical analyzer - interviewer gave tokens. expressions like "a*b" etc.
27. Besides communication cost, what is the other source of inefficiency in RPC? (answer : context switches, excessive buffer copying). How can you optimize the communication? (ans : communicate through shared memory on same machine, bypassing the kernel _ A Univ. of Wash. thesis)
28. Write a routine that prints out a 2-D array in spiral order!
29. How is the readers-writers problem solved? - using semaphores/ada .. etc.
30. Ways of optimizing symbol table storage in compilers.
31. A walk-through through the symbol table functions, lookup() implementation etc. - The interviewer was on the Microsoft C team.
32. A version of the "There are three persons X Y Z, one of which always lies".. etc..
33. There are 3 ants at 3 corners of a triangle, they randomly start moving towards another corner.. what is the probability that they don't collide.
34. Write an efficient algorithm and C code to shuffle a pack of cards.. this one was a feedback process until we came up with one with no extra storage.
35. The if (x == 0) y = 0 etc..
36. Some more bitwise optimization at assembly level
37. Some general questions on Lex, Yacc etc.
38. Given an array t[100] which contains numbers between 1..99. Return the duplicated value. Try both O(n) and O(n-square).
39. Given an array of characters. How would you reverse it. ? How would you reverse it without using indexing in the array.
40. Given a sequence of characters. How will you convert the lower case characters to upper case characters. ( Try using bit vector - solutions given in the C lib -typec.h)
41. Fundamentals of RPC.
42. Given a linked list which is sorted. How will u insert in sorted way.
43. Given a linked list How will you reverse it.
44. Give a good data structure for having n queues ( n not fixed) in a finite memory segment. You can have some data-structure separate for each queue. Try to use at least 90% of the memory space.
45. Do a breadth first traversal of a tree.
46. Write code for reversing a linked list.
47. Write, efficient code for extracting unique elements from a sorted list of array. e.g. (1, 1, 3, 3, 3, 5, 5, 5, 9, 9, 9, 9) -> (1, 3, 5, 9).
48. Given an array of integers, find the contiguous sub-array with the largest sum.
ANS. Can be done in O(n) time and O(1) extra space. Scan array from 1 to n. Remember the best sub-array seen so far and the best sub-array ending in i.
49. Given an array of length N containing integers between 1 and N, determine if it contains any duplicates.
ANS. [Is there an O(n) time solution that uses only O(1) extra space and does not destroy the original array?]
50. Sort an array of size n containing integers between 1 and K, given a temporary scratch integer array of size K.
ANS. Compute cumulative counts of integers in the auxiliary array. Now scan the original array, rotating cycles! [Can someone word this more nicely?]
* 51. An array of size k contains integers between 1 and n. You are given an additional scratch array of size n. Compress the original array by removing duplicates in it. What if k << n? ANS. Can be done in O(k) time i.e. without initializing the auxiliary array! 52. An array of integers. The sum of the array is known not to overflow an integer. Compute the sum. What if we know that integers are in 2's complement form? ANS. If numbers are in 2's complement, an ordinary looking loop like for(i=total=0;i< n;total+=array[i++]); will do. No need to check for overflows! 53. An array of characters. Reverse the order of words in it. ANS. Write a routine to reverse a character array. Now call it for the given array and for each word in it. * 54. An array of integers of size n. Generate a random permutation of the array, given a function rand_n() that returns an integer between 1 and n, both inclusive, with equal probability. What is the expected time of your algorithm? ANS. "Expected time" should ring a bell. To compute a random permutation, use the standard algorithm of scanning array from n downto 1, swapping i-th element with a uniformly random element <= i-th. To compute a uniformly random integer between 1 and k (k < n), call rand_n() repeatedly until it returns a value in the desired range. 55. An array of pointers to (very long) strings. Find pointers to the (lexicographically) smallest and largest strings. ANS. Scan array in pairs. Remember largest-so-far and smallest-so-far. Compare the larger of the two strings in the current pair with largest-so-far to update it. And the smaller of the current pair with the smallest-so-far to update it. For a total of <= 3n/2 strcmp() calls. That's also the lower bound. 56. Write a program to remove duplicates from a sorted array. ANS. int remove_duplicates(int * p, int size) { int current, insert = 1; for (current=1; current < size; current++) if (p[current] != p[insert-1]) { p[insert] = p[current]; current++; insert++; } else current++; return insert; } 57. C++ ( what is virtual function ? what happens if an error occurs in constructor or destructor. Discussion on error handling, templates, unique features of C++. What is different in C++, ( compare with unix). 58. Given a list of numbers ( fixed list) Now given any other list, how can you efficiently find out if there is any element in the second list that is an element of the first list (fixed list). 59. Given 3 lines of assembly code : find it is doing. IT was to find absolute value. 60. If you are on a boat and you throw out a suitcase, Will the level of water increase. 61. Print an integer using only putchar. Try doing it without using extra storage. 62. Write C code for (a) deleting an element from a linked list (b) traversing a linked list 63. What are various problems unique to distributed databases 64. Declare a void pointer ANS. void *ptr; 65. Make the pointer aligned to a 4 byte boundary in a efficient manner ANS. Assign the pointer to a long number and the number with 11...1100 add 4 to the number 66. What is a far pointer (in DOS) 67. What is a balanced tree 68. Given a linked list with the following property node2 is left child of node1, if node2 < node1 else, it is the right child. O P | | O A | | O B | | O C How do you convert the above linked list to the form without disturbing the property. Write C code for that. O P | | O B / \ / \ / \ O ? O ? determine where do A and C go 69. Describe the file system layout in the UNIX OS ANS. describe boot block, super block, inodes and data layout 70. In UNIX, are the files allocated contiguous blocks of data ANS. no, they might be fragmented How is the fragmented data kept track of ANS. Describe the direct blocks and indirect blocks in UNIX file system 71. Write an efficient C code for 'tr' program. 'tr' has two command line arguments. They both are strings of same length. tr reads an input file, replaces each character in the first string with the corresponding character in the second string. eg. 'tr abc xyz' replaces all 'a's by 'x's, 'b's by 'y's and so on. ANS. a) have an array of length 26. put 'x' in array element corr to 'a' put 'y' in array element corr to 'b' put 'z' in array element corr to 'c' put 'd' in array element corr to 'd' put 'e' in array element corr to 'e' and so on. the code while (!eof) { c = getc(); putc(array[c - 'a']); } 72. what is disk interleaving 73. why is disk interleaving adopted 74. given a new disk, how do you determine which interleaving is the best a) give 1000 read operations with each kind of interleaving determine the best interleaving from the statistics 75. draw the graph with performance on one axis and 'n' on another, where 'n' in the 'n' in n-way disk interleaving. (a tricky question, should be answered carefully) 76. I was a c++ code and was asked to find out the bug in that. The bug was that he declared an object locally in a function and tried to return the pointer to that object. Since the object is local to the function, it no more exists after returning from the function. The pointer, therefore, is invalid outside. 77. A real life problem - A square picture is cut into 16 squares and they are shuffled. Write a program to rearrange the 16 squares to get the original big square. 78. int *a; char *c; *(a) = 20; *c = *a; printf("%c",*c); what is the output? 79. Write a program to find whether a given m/c is big-endian or little-endian! 80. What is a volatile variable? 81. What is the scope of a static function in C ? 82. What is the difference between "malloc" and "calloc"? 83. struct n { int data; struct n* next}node; node *c,*t; c->data = 10;
t->next = null;
*c = *t;
what is the effect of the last statement?
84. If you're familiar with the ? operator x ? y : z
you want to implement that in a function: int cond(int x, int y, int z); using only ~, !, ^, &, +, |, <<, >> no if statements, or loops or anything else, just those operators, and the function should correctly return y or z based on the value of x. You may use constants, but only 8 bit constants. You can cast all you want. You're not supposed to use extra variables, but in the end, it won't really matter, using vars just makes things cleaner. You should be able to reduce your solution to a single line in the end though that requires no extra vars.
85. You have an abstract computer, so just forget everything you know about computers, this one only does what I'm about to tell you it does. You can use as many variables as you need, there are no negative numbers, all numbers are integers. You do not know the size of the integers, they could be infinitely large, so you can't count on truncating at any point. There are NO comparisons allowed, no if statements or anything like that. There are only four operations you can do on a variable.
1) You can set a variable to 0.
2) You can set a variable = another variable.
3) You can increment a variable (only by 1), and it's a post increment.
4) You can loop. So, if you were to say loop(v1) and v1 = 10, your loop would execute 10 times, but the value in v1 wouldn't change so the first line in the loop can change value of v1 without changing the number of times you loop.
You need to do 3 things.
1) Write a function that decrements by 1.
2) Write a function that subtracts one variable from another.
3) Write a function that divides one variable by another.
4) See if you can implement all 3 using at most 4 variables. Meaning, you're not making function calls now, you're making macros. And at most you can have 4 variables. The restriction really only applies to divide, the other 2 are easy to do with 4 vars or less. Division on the other hand is dependent on the other 2 functions, so, if subtract requires 3 variables, then divide only has 1 variable left unchanged after a call to subtract. Basically, just make your function calls to decrement and subtract so you pass your vars in by reference, and you can't declare any new variables in a function, what you pass in is all it gets.
Linked lists
* 86. Under what circumstances can one delete an element from a singly linked list in constant time?
ANS. If the list is circular and there are no references to the nodes in the list from anywhere else! Just copy the contents of the next node and delete the next node. If the list is not circular, we can delete any but the last node using this idea. In that case, mark the last node as dummy!
* 87. Given a singly linked list, determine whether it contains a loop or not.
ANS. (a) Start reversing the list. If you reach the head, gotcha! there is a loop!
But this changes the list. So, reverse the list again.
(b) Maintain two pointers, initially pointing to the head. Advance one of them one node at a time. And the other one, two nodes at a time. If the latter overtakes the former at any time, there is a loop!
p1 = p2 = head;
do {
p1 = p1->next;
p2 = p2->next->next;
} while (p1 != p2);
88. Given a singly linked list, print out its contents in reverse order. Can you do it without using any extra space?
ANS. Start reversing the list. Do this again, printing the contents.
89. Given a binary tree with nodes, print out the values in pre-order/in-order/post-order without using any extra space.
90. Reverse a singly linked list recursively. The function prototype is node * reverse (node *) ;
ANS.
node * reverse (node * n)
{
node * m ;
if (! (n && n -> next))
return n ;
m = reverse (n -> next) ;
n -> next -> next = n ;
n -> next = NULL ;
return m ;
}
91. Given a singly linked list, find the middle of the list.
HINT. Use the single and double pointer jumping. Maintain two pointers, initially pointing to the head. Advance one of them one node at a time. And the other one, two nodes at a time. When the double reaches the end, the single is in the middle. This is not asymptotically faster but seems to take less steps than going through the list twice.
Bit-manipulation
92. Reverse the bits of an unsigned integer.
ANS.
#define reverse(x) \
(x=x>>16|(0x0000ffff&x)<<16, \ x=(0xff00ff00&x)>>8|(0x00ff00ff&x)<<8, \ x=(0xf0f0f0f0&x)>>4|(0x0f0f0f0f&x)<<4, \ x=(0xcccccccc&x)>>2|(0x33333333&x)<<2, \ x=(0xaaaaaaaa&x)>>1|(0x55555555&x)<<1) * 93. Compute the number of ones in an unsigned integer. ANS. #define count_ones(x) \ (x=(0xaaaaaaaa&x)>>1+(0x55555555&x), \
x=(0xcccccccc&x)>>2+(0x33333333&x), \
x=(0xf0f0f0f0&x)>>4+(0x0f0f0f0f&x), \
x=(0xff00ff00&x)>>8+(0x00ff00ff&x), \
x=x>>16+(0x0000ffff&x))
94. Compute the discrete log of an unsigned integer.
ANS.
#define discrete_log(h) \
(h=(h>>1)|(h>>2), \
h|=(h>>2), \
h|=(h>>4), \
h|=(h>>8), \
h|=(h>>16), \
h=(0xaaaaaaaa&h)>>1+(0x55555555&h), \
h=(0xcccccccc&h)>>2+(0x33333333&h), \
h=(0xf0f0f0f0&h)>>4+(0x0f0f0f0f&h), \
h=(0xff00ff00&h)>>8+(0x00ff00ff&h), \
h=(h>>16)+(0x0000ffff&h))
If I understand it right, log2(2) =1, log2(3)=1, log2(4)=2..... But this macro does not work out log2(0) which does not exist! How do you think it should be handled?
* 95. How do we test most simply if an unsigned integer is a power of two?
ANS. #define power_of_two(x) \ ((x)&&(~(x&(x-1))))
96. Set the highest significant bit of an unsigned integer to zero.
ANS. (from Denis Zabavchik) Set the highest significant bit of an unsigned integer to zero
#define zero_most_significant(h) \
(h&=(h>>1)|(h>>2), \
h|=(h>>2), \
h|=(h>>4), \
h|=(h>>8), \
h|=(h>>16))
97. Let f(k) = y where k is the y-th number in the increasing sequence of non-negative integers with the same number of ones in its binary representation as y, e.g. f(0) = 1, f(1) = 1, f(2) = 2, f(3) = 1, f(4) = 3, f(5) = 2, f(6) = 3 and so on. Given k >= 0, compute f(k).
Others
98. A character set has 1 and 2 byte characters. One byte characters have 0 as the first bit. You just keep accumulating the characters in a buffer. Suppose at some point the user types a backspace, how can you remove the character efficiently. (Note: You cant store the last character typed because the user can type in arbitrarily many backspaces)
99. What is the simples way to check if the sum of two unsigned integers has resulted in an overflow.
100. How do you represent an n-ary tree? Write a program to print the nodes of such a tree in breadth first order.
101. Write the 'tr' program of UNIX. Invoked as
tr -str1 -str2. It reads stdin and prints it out to stdout, replacing every occurance of str1[i] with str2[i].
e.g. tr -abc -xyz
to be and not to be <- input
to ye xnd not to ye <- output
Networks and Security
1. How do you use RSA for both authentication and secrecy?
2. What is ARP and how does it work?
3. What's the difference between a switch and a router?
4. Name some routing protocols? (RIP,OSPF etc..)
5. How do you do authentication with message digest(MD5)? (Usually MD is used for finding tampering of data)
6. How do you implement a packet filter that distinguishes following cases and selects first case and rejects second case.
i) A host inside the corporate n/w makes a ftp request to outside host and the outside host sends reply.
ii) A host outside the network sends a ftp request to host inside. for the packet filter in both cases the source and destination fields will look the same.
7. How does traceroute work? Now how does traceroute make sure that the packet follows the same path that a previous (with ttl - 1) probe packet went in?
8. Explain Kerberos Protocol ?
9. What are digital signatures and smart cards?
10. Difference between discretionary access control and mandatory access control?
Java
1. How do you find the size of a java object (not the primitive type) ?
ANS. type cast it to string and find its s.length()
2. Why is multiple inheritance not provided in Java?
3. Thread t = new Thread(); t.start(); t = null; now what will happen to the created thread?
4. How is garbage collection done in java?
5. How do you write a "ping" routine in java?
6. What are the security restrictions on applets?
Graphics
1. Write a function to check if two rectangles defined as below overlap or not. struct rect { int top, bot, left, right; } r1, r2;
2. Write a SetPixel(x, y) function, given a pointer to the bitmap. Each pixel is represented by 1 bit. There are 640 pixels per row. In each byte, while the bits are numbered right to left, pixels are numbered left to right. Avoid multiplications and divisions to improve performance.
Databases
* 1. You, a designer want to measure disk traffic i.e. get a histogram showing the relative frequency of I/O/second for each disk block. The buffer pool has b buffers and uses LRU replacement policy. The disk block size and buffer pool block sizes are the same. You are given a routine int lru_block_in_position (int i) which returns the block_id of the block in the i-th position in the list of blocks managed by LRU. Assume position 0 is the hottest. You can repeatedly call this routine. How would you get the histogram you desire?
Hints and Answers
1. Simply do histogram [lru_block_in_position (b-1)] ++ at frequent intervals... The sampling frequency should be close to the disk I/O rate. It can be adjusted by remembering the last block seen in position b. If same, decrease frequency; if different, increase, with exponential decay etc. And of course, take care of overflows in the histogram.
Semaphores
1. Implement a multiple-reader-single-writer lock given a compare-and-swap instruction. Readers cannot overtake waiting writers.
Computer Architecture
1. Explain what is DMA?
2. What is pipelining?
3. What are superscalar machines and vliw machines?
4. What is cache?
5. What is cache coherency and how is it eliminated?
6. What is write back and write through caches?
7. What are different pipelining hazards and how are they eliminated.
8. What are different stages of a pipe?
9. Explain more about branch prediction in controlling the control hazards
10. Give examples of data hazards with pseudo codes.
11. How do you calculate the number of sets given its way and size in a cache?
12. How is a block found in a cache?
13. Scoreboard analysis.
14. What is miss penalty and give your own ideas to eliminate it.
15. How do you improve the cache performance.
16. Different addressing modes.
17. Computer arithmetic with two's complements.
18. About hardware and software interrupts.
19. What is bus contention and how do you eliminate it.
20. What is aliasing?
21) What is the difference between a latch and a flip flop?
22) What is the race around condition? How can it be overcome?
23) What is the purpose of cache? How is it used?
24) What are the types of memory management?
Kiran Bondalapati Homepage
Disclaimer: This page is in no way connected with Microsoft Corporation, its affiliates, friends or haters
This page is moving to http://www.softwareinterview.com. Please update your bookmarks.
What?
Here is a set of questions that I have with me which software guys have asked at interviews in the past, most of them are actually from Microsoft but a few have been pulled together from other places too. I have collected these from friends and would welcome any additions from you. Mail them to kiran AT usc DOT edu. Do send me your solutions, but the intent of this page is to kindle enough interest in you to try similar logic and programming questions.
PLEASE DO NOT REQUEST ME FOR MORE SOLUTIONS!
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Why?
I have grown up reading Martin Gardner's Scientific American columns on Mathematical Games and interesting mathematics olympiad problems in high school. I discovered, to my delight, Bentley's Programming Pearls and David Gries' The Science of Programming in my computer science education. There is underlying beauty in mathematics and computer science. Some find it and others hate the subjects. When I found some of the Microsoft interview questions in graduate school, they were similar to mathematical puzzles that I was interested in. I started collecting them more as an illustration of interesting logic puzzles and algorithms in programming, than as an interview aid. If it has morphed into an interview questions page, that is more due to interest from all interviewees out there.
Some of the programming questions have a basic foundation in mathematics and algorithms. If the given data structure has a specific amount of information and the question asks you to extract/modify the given information, it is possible (though not always obvious) to find optimal solutions, and prove that it cannot be done any better, by quantifying the information content. But, there are always elegant and ugly ways to extract the same information. When you manage to find out the optimal solution to a problem, it usually not only turns out to be elegant, but also has the "aha!" factor to it. Try proving on paper the following question from my undergraduate mid-term:
1. Everyone Loves All Lovers
2. Romeo Loves Juliet
Therefore, prove (i.e. 1 AND 2 => 3)
3. I Love You
How?
To answer one of the more frequent questions that I get: No! I have never interviewed at Microsoft. In fact, I work in a microprocessor company far removed from any software development (though I work mostly in programming). However, I have had two of my roommates and two more housemates eventually working in Microsoft, in addition to a large number of friends. None of them have contributed to this page AFTER they started working at Microsoft. Microsoft itself does not hold any patents and nor has it invented most of the questions. Most of them come from mathematics and physics books, party puzzles, programming lore and standard textbooks. I know many companies ask similar questions, though Microsoft might have made the practice more common (especially with the manhole cover type of questions).
Usage
I have spent some time in collecting with the intention of their value as a practice session. They are not meant to be exact questions that you need to know and answer in an interview. They are supposed to make you think! Discuss with your friends, colleagues, professors for answers (get your tuition money's worth). I have left the page in simple text format so you can print them out and try them on your flight to the interview in case you are pressed for time. One of the strangest phone calls I remember is from a girl, staying up in a Microsoft provided hotel room in Redmond the night before the interview, asking me about the solution for one of the questions from this page. I hope the rest of you are saner (or do not have my phone number).
Kiran Bondalapati Ze Meat
Puzzles, Riddles, etc.
Programming Questions
Computer Networks, Databases, etc.
Computer Architecture
Puzzles, Riddles and Others
0. Classic: If a bear walks one mile south, turns left and walks one mile to the east and then turns left again and walks one mile north and arrives at its original position, what is the color of the bear.
ANS. The color of the bear is trivial. The possible solutions to it are interesting. In addition to the trivial north pole, there are additional circles near south pole. Think it out.
* 1. Given a rectangular (cuboidal for the puritans) cake with a rectangular piece removed (any size or orientation), how would you cut the remainder of the cake into two equal halves with one straight cut of a knife?
ANS. Join the centers of the original and the removed rectangle. It works for cuboids too! BTW, I have been getting many questions asking why a horizontal slice across the middle will not do. Please note the "any size or orientation" in the question! Don't get boxed in by the way you cut your birthday cake :) Think out of the box.
2. There are 3 baskets. one of them have apples, one has oranges only and the other has mixture of apples and oranges. The labels on their baskets always lie. (i.e. if the label says oranges, you are sure that it doesn't have oranges only,it could be a mixture) The task is to pick one basket and pick only one fruit from it and then correctly label all the three baskets.
HINT. There are only two combinations of distributions in which ALL the baskets have wrong labels. By picking a fruit from the one labeled MIXTURE, it is possible to tell what the other two baskets have.
3. You have 8 balls. One of them is defective and weighs less than others. You have a balance to measure balls against each other. In 2 weighings how do you find the defective one?
4. Why is a manhole cover round?
HINT. The diagonal of a square hole is larger than the side of a cover!
Alternate answers: 1. Round covers can be transported by one person, because they can be rolled on their edge. 2. A round cover doesn't need to be rotated to fit over a hole.
5. How many cars are there in the USA?
6. You've got someone working for you for seven days and a gold bar to pay them. The gold bar is segmented into seven connected pieces. You must give them a piece of gold at the end of every day. If you are only allowed to make two breaks in the gold bar, how do you pay your worker?
7. One train leaves Los Angeles at 15mph heading for New York. Another train leaves from New York at 20mph heading for Los Angeles on the same track. If a bird, flying at 25mph, leaves from Los Angeles at the same time as the train and flies back and forth between the two trains until they collide, how far will the bird have traveled?
HINT. Think relative speed of the trains.
8. You have two jars, 50 red marbles and 50 blue marbles. A jar will be picked at random, and then a marble will be picked from the jar. Placing all of the marbles in the jars, how can you maximize the chances of a red marble being picked? What are the exact odds of getting a red marble using your scheme?
9. Imagine you are standing in front of a mirror, facing it. Raise your left hand. Raise your right hand. Look at your reflection. When you raise your left hand your reflection raises what appears to be his right hand. But when you tilt your head up, your reflection does too, and does not appear to tilt his/her head down. Why is it that the mirror appears to reverse left and right, but not up and down?
10. You have 5 jars of pills. Each pill weighs 10 gram, except for contaminated pills contained in one jar, where each pill weighs 9 gm. Given a scale, how could you tell which jar had the contaminated pills in just one measurement?
ANS. 1. Mark the jars with numbers 1, 2, 3, 4, and 5.
2. Take 1 pill from jar 1, take 2 pills from jar 2, take 3 pills from jar 3, take 4 pills from jar 4 and take 5 pills from jar 5.
3. Put all of them on the scale at once and take the measurement.
4. Now, subtract the measurement from 150 ( 1*10 + 2*10 + 3*10 + 4*10 + 5*10)
5. The result will give you the jar number which has contaminated pill.
11. If you had an infinite supply of water and a 5 quart and 3 quart pail, how would you measure exactly 4 quarts?
12. You have a bucket of jelly beans. Some are red, some are blue, and some green. With your eyes closed, pick out 2 of a like color. How many do you have to grab to be sure you have 2 of the same?
13. Which way should the key turn in a car door to unlock it?
14. If you could remove any of the 50 states, which state would it be and why?
15. There are four dogs/ants/people at four corners of a square of unit distance. At the same instant all of them start running with unit speed towards the person on their clockwise direction and will always run towards that target. How long does it take for them to meet and where?
HINT. They will meet in the center and the distance covered by them is independent of the path they actually take (a spiral).
16. (from Tara Hovel) A helicopter drops two trains, each on a parachute, onto a straight infinite railway line. There is an undefined distance between the two trains. Each faces the same direction, and upon landing, the parachute attached to each train falls to the ground next to the train and detaches. Each train has a microchip that controls its motion. The chips are identical. There is no way for the trains to know where they are. You need to write the code in the chip to make the trains bump into each other. Each line of code takes a single clock cycle to execute.
You can use the following commands (and only these);
MF - moves the train forward
MB - moves the train backward
IF (P) - conditional that's satisfied if the train is next to a parachute. There is no "then" to this IF statement.
GOTO
ANS.
A: MF
IF (P)
GOTO B
GOTO A
-----
B: MF
GOTO B
Explanation: The first line simply gets them off the parachutes. You need to get the trains off their parachutes so the back train can find the front train's parachute, creating a special condition that will allow it to break out of the code they both have to follow initially. They both loop through A: until the back train finds the front train's parachute, at which point it goes to B: and gets stuck in that loop. The front train still hasn't found a parachute, so it keeps in the A loop. Because each line of code takes a "clock cycle" to execute, it takes longer to execute the A loop than the B loop, therefore the back train (running in the B loop) will catch up to the front train.
Personality
It is best to read some website or a book for questions like these.
1. Tell me the courses you liked and why did you like them.
2. Give an instance in your life in which you were faced with a problem and you tackled it successfully.
3. What is your ideal working environment.
4. Why do you think you are smart.
5. Questions on the projects listed on the Resume.
6. Do you want to know any thing about the company.( Try to ask some relevant and interesting question).
7. How long do you want to stay in USA and why (I guess non-citizens get this)?
8. What is your geographical preference?
9. What are your expectations from the job.
Algorithms and Programming
1. Given a rectangular (cuboidal for the puritans) cake with a rectangular piece removed (any size or orientation), how would you cut the remainder of the cake into two equal halves with one straight cut of a knife ?
2. You're given an array containing both positive and negative integers and required to find the sub-array with the largest sum (O(N) a la KBL). Write a routine in C for the above.
3. Given an array of size N in which every number is between 1 and N, determine if there are any duplicates in it. You are allowed to destroy the array if you like. [ I ended up giving about 4 or 5 different solutions for this, each supposedly better than the others ].
4. Write a routine to draw a circle (x ** 2 + y ** 2 = r ** 2) without making use of any floating point computations at all. [ This one had me stuck for quite some time and I first gave a solution that did have floating point computations ].
5. Given only putchar (no sprintf, itoa, etc.) write a routine putlong that prints out an unsigned long in decimal. [ I gave the obvious solution of taking % 10 and / 10, which gives us the decimal value in reverse order. This requires an array since we need to print it out in the correct order. The interviewer wasn't too pleased and asked me to give a solution which didn't need the array ].
6. Give a one-line C expression to test whether a number is a power of 2. [No loops allowed - it's a simple test.]
7. Given an array of characters which form a sentence of words, give an efficient algorithm to reverse the order of the words (not characters) in it.
8. How many points are there on the globe where by walking one mile south, one mile east and one mile north you reach the place where you started.
9. Give a very good method to count the number of ones in a "n" (e.g. 32) bit number.
ANS. Given below are simple solutions, find a solution that does it in log (n) steps.
Iterative
function iterativecount (unsigned int n)
begin
int count=0;
while (n)
begin
count += n & 0x1 ;
n >>= 1;
end
return count;
end
Sparse Count
function sparsecount (unsigned int n)
begin
int count=0;
while (n)
begin
count++;
n &= (n-1);
end
return count ;
end
10. What are the different ways to implement a condition where the value of x can be either a 0 or a 1. Apparently the if then else solution has a jump when written out in assembly. if (x == 0) y=a else y=b There is a logical, arithmetic and a data structure solution to the above problem.
11. Reverse a linked list.
12. Insert in a sorted list
13. In a X's and 0's game (i.e. TIC TAC TOE) if you write a program for this give a fast way to generate the moves by the computer. I mean this should be the fastest way possible.
The answer is that you need to store all possible configurations of the board and the move that is associated with that. Then it boils down to just accessing the right element and getting the corresponding move for it. Do some analysis and do some more optimization in storage since otherwise it becomes infeasible to get the required storage in a DOS machine.
14. I was given two lines of assembly code which found the absolute value of a number stored in two's complement form. I had to recognize what the code was doing. Pretty simple if you know some assembly and some fundaes on number representation.
15. Give a fast way to multiply a number by 7.
16. How would go about finding out where to find a book in a library. (You don't know how exactly the books are organized beforehand).
17. Linked list manipulation.
18. Tradeoff between time spent in testing a product and getting into the market first.
19. What to test for given that there isn't enough time to test everything you want to.
20. First some definitions for this problem: a) An ASCII character is one byte long and the most significant bit in the byte is always '0'. b) A Kanji character is two bytes long. The only characteristic of a Kanji character is that in its first byte the most significant bit is '1'.
Now you are given an array of a characters (both ASCII and Kanji) and, an index into the array. The index points to the start of some character. Now you need to write a function to do a backspace (i.e. delete the character before the given index).
21. Delete an element from a doubly linked list.
22. Write a function to find the depth of a binary tree.
23. Given two strings S1 and S2. Delete from S2 all those characters which occur in S1 also and finally create a clean S2 with the relevant characters deleted.
24. Assuming that locks are the only reason due to which deadlocks can occur in a system. What would be a foolproof method of avoiding deadlocks in the system.
25. Reverse a linked list.
Ans: Possible answers -
iterative loop
curr->next = prev;
prev = curr;
curr = next;
next = curr->next
endloop
recursive reverse(ptr)
if (ptr->next == NULL)
return ptr;
temp = reverse(ptr->next);
temp->next = ptr;
return ptr;
end
26. Write a small lexical analyzer - interviewer gave tokens. expressions like "a*b" etc.
27. Besides communication cost, what is the other source of inefficiency in RPC? (answer : context switches, excessive buffer copying). How can you optimize the communication? (ans : communicate through shared memory on same machine, bypassing the kernel _ A Univ. of Wash. thesis)
28. Write a routine that prints out a 2-D array in spiral order!
29. How is the readers-writers problem solved? - using semaphores/ada .. etc.
30. Ways of optimizing symbol table storage in compilers.
31. A walk-through through the symbol table functions, lookup() implementation etc. - The interviewer was on the Microsoft C team.
32. A version of the "There are three persons X Y Z, one of which always lies".. etc..
33. There are 3 ants at 3 corners of a triangle, they randomly start moving towards another corner.. what is the probability that they don't collide.
34. Write an efficient algorithm and C code to shuffle a pack of cards.. this one was a feedback process until we came up with one with no extra storage.
35. The if (x == 0) y = 0 etc..
36. Some more bitwise optimization at assembly level
37. Some general questions on Lex, Yacc etc.
38. Given an array t[100] which contains numbers between 1..99. Return the duplicated value. Try both O(n) and O(n-square).
39. Given an array of characters. How would you reverse it. ? How would you reverse it without using indexing in the array.
40. Given a sequence of characters. How will you convert the lower case characters to upper case characters. ( Try using bit vector - solutions given in the C lib -typec.h)
41. Fundamentals of RPC.
42. Given a linked list which is sorted. How will u insert in sorted way.
43. Given a linked list How will you reverse it.
44. Give a good data structure for having n queues ( n not fixed) in a finite memory segment. You can have some data-structure separate for each queue. Try to use at least 90% of the memory space.
45. Do a breadth first traversal of a tree.
46. Write code for reversing a linked list.
47. Write, efficient code for extracting unique elements from a sorted list of array. e.g. (1, 1, 3, 3, 3, 5, 5, 5, 9, 9, 9, 9) -> (1, 3, 5, 9).
48. Given an array of integers, find the contiguous sub-array with the largest sum.
ANS. Can be done in O(n) time and O(1) extra space. Scan array from 1 to n. Remember the best sub-array seen so far and the best sub-array ending in i.
49. Given an array of length N containing integers between 1 and N, determine if it contains any duplicates.
ANS. [Is there an O(n) time solution that uses only O(1) extra space and does not destroy the original array?]
50. Sort an array of size n containing integers between 1 and K, given a temporary scratch integer array of size K.
ANS. Compute cumulative counts of integers in the auxiliary array. Now scan the original array, rotating cycles! [Can someone word this more nicely?]
* 51. An array of size k contains integers between 1 and n. You are given an additional scratch array of size n. Compress the original array by removing duplicates in it. What if k << n? ANS. Can be done in O(k) time i.e. without initializing the auxiliary array! 52. An array of integers. The sum of the array is known not to overflow an integer. Compute the sum. What if we know that integers are in 2's complement form? ANS. If numbers are in 2's complement, an ordinary looking loop like for(i=total=0;i< n;total+=array[i++]); will do. No need to check for overflows! 53. An array of characters. Reverse the order of words in it. ANS. Write a routine to reverse a character array. Now call it for the given array and for each word in it. * 54. An array of integers of size n. Generate a random permutation of the array, given a function rand_n() that returns an integer between 1 and n, both inclusive, with equal probability. What is the expected time of your algorithm? ANS. "Expected time" should ring a bell. To compute a random permutation, use the standard algorithm of scanning array from n downto 1, swapping i-th element with a uniformly random element <= i-th. To compute a uniformly random integer between 1 and k (k < n), call rand_n() repeatedly until it returns a value in the desired range. 55. An array of pointers to (very long) strings. Find pointers to the (lexicographically) smallest and largest strings. ANS. Scan array in pairs. Remember largest-so-far and smallest-so-far. Compare the larger of the two strings in the current pair with largest-so-far to update it. And the smaller of the current pair with the smallest-so-far to update it. For a total of <= 3n/2 strcmp() calls. That's also the lower bound. 56. Write a program to remove duplicates from a sorted array. ANS. int remove_duplicates(int * p, int size) { int current, insert = 1; for (current=1; current < size; current++) if (p[current] != p[insert-1]) { p[insert] = p[current]; current++; insert++; } else current++; return insert; } 57. C++ ( what is virtual function ? what happens if an error occurs in constructor or destructor. Discussion on error handling, templates, unique features of C++. What is different in C++, ( compare with unix). 58. Given a list of numbers ( fixed list) Now given any other list, how can you efficiently find out if there is any element in the second list that is an element of the first list (fixed list). 59. Given 3 lines of assembly code : find it is doing. IT was to find absolute value. 60. If you are on a boat and you throw out a suitcase, Will the level of water increase. 61. Print an integer using only putchar. Try doing it without using extra storage. 62. Write C code for (a) deleting an element from a linked list (b) traversing a linked list 63. What are various problems unique to distributed databases 64. Declare a void pointer ANS. void *ptr; 65. Make the pointer aligned to a 4 byte boundary in a efficient manner ANS. Assign the pointer to a long number and the number with 11...1100 add 4 to the number 66. What is a far pointer (in DOS) 67. What is a balanced tree 68. Given a linked list with the following property node2 is left child of node1, if node2 < node1 else, it is the right child. O P | | O A | | O B | | O C How do you convert the above linked list to the form without disturbing the property. Write C code for that. O P | | O B / \ / \ / \ O ? O ? determine where do A and C go 69. Describe the file system layout in the UNIX OS ANS. describe boot block, super block, inodes and data layout 70. In UNIX, are the files allocated contiguous blocks of data ANS. no, they might be fragmented How is the fragmented data kept track of ANS. Describe the direct blocks and indirect blocks in UNIX file system 71. Write an efficient C code for 'tr' program. 'tr' has two command line arguments. They both are strings of same length. tr reads an input file, replaces each character in the first string with the corresponding character in the second string. eg. 'tr abc xyz' replaces all 'a's by 'x's, 'b's by 'y's and so on. ANS. a) have an array of length 26. put 'x' in array element corr to 'a' put 'y' in array element corr to 'b' put 'z' in array element corr to 'c' put 'd' in array element corr to 'd' put 'e' in array element corr to 'e' and so on. the code while (!eof) { c = getc(); putc(array[c - 'a']); } 72. what is disk interleaving 73. why is disk interleaving adopted 74. given a new disk, how do you determine which interleaving is the best a) give 1000 read operations with each kind of interleaving determine the best interleaving from the statistics 75. draw the graph with performance on one axis and 'n' on another, where 'n' in the 'n' in n-way disk interleaving. (a tricky question, should be answered carefully) 76. I was a c++ code and was asked to find out the bug in that. The bug was that he declared an object locally in a function and tried to return the pointer to that object. Since the object is local to the function, it no more exists after returning from the function. The pointer, therefore, is invalid outside. 77. A real life problem - A square picture is cut into 16 squares and they are shuffled. Write a program to rearrange the 16 squares to get the original big square. 78. int *a; char *c; *(a) = 20; *c = *a; printf("%c",*c); what is the output? 79. Write a program to find whether a given m/c is big-endian or little-endian! 80. What is a volatile variable? 81. What is the scope of a static function in C ? 82. What is the difference between "malloc" and "calloc"? 83. struct n { int data; struct n* next}node; node *c,*t; c->data = 10;
t->next = null;
*c = *t;
what is the effect of the last statement?
84. If you're familiar with the ? operator x ? y : z
you want to implement that in a function: int cond(int x, int y, int z); using only ~, !, ^, &, +, |, <<, >> no if statements, or loops or anything else, just those operators, and the function should correctly return y or z based on the value of x. You may use constants, but only 8 bit constants. You can cast all you want. You're not supposed to use extra variables, but in the end, it won't really matter, using vars just makes things cleaner. You should be able to reduce your solution to a single line in the end though that requires no extra vars.
85. You have an abstract computer, so just forget everything you know about computers, this one only does what I'm about to tell you it does. You can use as many variables as you need, there are no negative numbers, all numbers are integers. You do not know the size of the integers, they could be infinitely large, so you can't count on truncating at any point. There are NO comparisons allowed, no if statements or anything like that. There are only four operations you can do on a variable.
1) You can set a variable to 0.
2) You can set a variable = another variable.
3) You can increment a variable (only by 1), and it's a post increment.
4) You can loop. So, if you were to say loop(v1) and v1 = 10, your loop would execute 10 times, but the value in v1 wouldn't change so the first line in the loop can change value of v1 without changing the number of times you loop.
You need to do 3 things.
1) Write a function that decrements by 1.
2) Write a function that subtracts one variable from another.
3) Write a function that divides one variable by another.
4) See if you can implement all 3 using at most 4 variables. Meaning, you're not making function calls now, you're making macros. And at most you can have 4 variables. The restriction really only applies to divide, the other 2 are easy to do with 4 vars or less. Division on the other hand is dependent on the other 2 functions, so, if subtract requires 3 variables, then divide only has 1 variable left unchanged after a call to subtract. Basically, just make your function calls to decrement and subtract so you pass your vars in by reference, and you can't declare any new variables in a function, what you pass in is all it gets.
Linked lists
* 86. Under what circumstances can one delete an element from a singly linked list in constant time?
ANS. If the list is circular and there are no references to the nodes in the list from anywhere else! Just copy the contents of the next node and delete the next node. If the list is not circular, we can delete any but the last node using this idea. In that case, mark the last node as dummy!
* 87. Given a singly linked list, determine whether it contains a loop or not.
ANS. (a) Start reversing the list. If you reach the head, gotcha! there is a loop!
But this changes the list. So, reverse the list again.
(b) Maintain two pointers, initially pointing to the head. Advance one of them one node at a time. And the other one, two nodes at a time. If the latter overtakes the former at any time, there is a loop!
p1 = p2 = head;
do {
p1 = p1->next;
p2 = p2->next->next;
} while (p1 != p2);
88. Given a singly linked list, print out its contents in reverse order. Can you do it without using any extra space?
ANS. Start reversing the list. Do this again, printing the contents.
89. Given a binary tree with nodes, print out the values in pre-order/in-order/post-order without using any extra space.
90. Reverse a singly linked list recursively. The function prototype is node * reverse (node *) ;
ANS.
node * reverse (node * n)
{
node * m ;
if (! (n && n -> next))
return n ;
m = reverse (n -> next) ;
n -> next -> next = n ;
n -> next = NULL ;
return m ;
}
91. Given a singly linked list, find the middle of the list.
HINT. Use the single and double pointer jumping. Maintain two pointers, initially pointing to the head. Advance one of them one node at a time. And the other one, two nodes at a time. When the double reaches the end, the single is in the middle. This is not asymptotically faster but seems to take less steps than going through the list twice.
Bit-manipulation
92. Reverse the bits of an unsigned integer.
ANS.
#define reverse(x) \
(x=x>>16|(0x0000ffff&x)<<16, \ x=(0xff00ff00&x)>>8|(0x00ff00ff&x)<<8, \ x=(0xf0f0f0f0&x)>>4|(0x0f0f0f0f&x)<<4, \ x=(0xcccccccc&x)>>2|(0x33333333&x)<<2, \ x=(0xaaaaaaaa&x)>>1|(0x55555555&x)<<1) * 93. Compute the number of ones in an unsigned integer. ANS. #define count_ones(x) \ (x=(0xaaaaaaaa&x)>>1+(0x55555555&x), \
x=(0xcccccccc&x)>>2+(0x33333333&x), \
x=(0xf0f0f0f0&x)>>4+(0x0f0f0f0f&x), \
x=(0xff00ff00&x)>>8+(0x00ff00ff&x), \
x=x>>16+(0x0000ffff&x))
94. Compute the discrete log of an unsigned integer.
ANS.
#define discrete_log(h) \
(h=(h>>1)|(h>>2), \
h|=(h>>2), \
h|=(h>>4), \
h|=(h>>8), \
h|=(h>>16), \
h=(0xaaaaaaaa&h)>>1+(0x55555555&h), \
h=(0xcccccccc&h)>>2+(0x33333333&h), \
h=(0xf0f0f0f0&h)>>4+(0x0f0f0f0f&h), \
h=(0xff00ff00&h)>>8+(0x00ff00ff&h), \
h=(h>>16)+(0x0000ffff&h))
If I understand it right, log2(2) =1, log2(3)=1, log2(4)=2..... But this macro does not work out log2(0) which does not exist! How do you think it should be handled?
* 95. How do we test most simply if an unsigned integer is a power of two?
ANS. #define power_of_two(x) \ ((x)&&(~(x&(x-1))))
96. Set the highest significant bit of an unsigned integer to zero.
ANS. (from Denis Zabavchik) Set the highest significant bit of an unsigned integer to zero
#define zero_most_significant(h) \
(h&=(h>>1)|(h>>2), \
h|=(h>>2), \
h|=(h>>4), \
h|=(h>>8), \
h|=(h>>16))
97. Let f(k) = y where k is the y-th number in the increasing sequence of non-negative integers with the same number of ones in its binary representation as y, e.g. f(0) = 1, f(1) = 1, f(2) = 2, f(3) = 1, f(4) = 3, f(5) = 2, f(6) = 3 and so on. Given k >= 0, compute f(k).
Others
98. A character set has 1 and 2 byte characters. One byte characters have 0 as the first bit. You just keep accumulating the characters in a buffer. Suppose at some point the user types a backspace, how can you remove the character efficiently. (Note: You cant store the last character typed because the user can type in arbitrarily many backspaces)
99. What is the simples way to check if the sum of two unsigned integers has resulted in an overflow.
100. How do you represent an n-ary tree? Write a program to print the nodes of such a tree in breadth first order.
101. Write the 'tr' program of UNIX. Invoked as
tr -str1 -str2. It reads stdin and prints it out to stdout, replacing every occurance of str1[i] with str2[i].
e.g. tr -abc -xyz
to be and not to be <- input
to ye xnd not to ye <- output
Networks and Security
1. How do you use RSA for both authentication and secrecy?
2. What is ARP and how does it work?
3. What's the difference between a switch and a router?
4. Name some routing protocols? (RIP,OSPF etc..)
5. How do you do authentication with message digest(MD5)? (Usually MD is used for finding tampering of data)
6. How do you implement a packet filter that distinguishes following cases and selects first case and rejects second case.
i) A host inside the corporate n/w makes a ftp request to outside host and the outside host sends reply.
ii) A host outside the network sends a ftp request to host inside. for the packet filter in both cases the source and destination fields will look the same.
7. How does traceroute work? Now how does traceroute make sure that the packet follows the same path that a previous (with ttl - 1) probe packet went in?
8. Explain Kerberos Protocol ?
9. What are digital signatures and smart cards?
10. Difference between discretionary access control and mandatory access control?
Java
1. How do you find the size of a java object (not the primitive type) ?
ANS. type cast it to string and find its s.length()
2. Why is multiple inheritance not provided in Java?
3. Thread t = new Thread(); t.start(); t = null; now what will happen to the created thread?
4. How is garbage collection done in java?
5. How do you write a "ping" routine in java?
6. What are the security restrictions on applets?
Graphics
1. Write a function to check if two rectangles defined as below overlap or not. struct rect { int top, bot, left, right; } r1, r2;
2. Write a SetPixel(x, y) function, given a pointer to the bitmap. Each pixel is represented by 1 bit. There are 640 pixels per row. In each byte, while the bits are numbered right to left, pixels are numbered left to right. Avoid multiplications and divisions to improve performance.
Databases
* 1. You, a designer want to measure disk traffic i.e. get a histogram showing the relative frequency of I/O/second for each disk block. The buffer pool has b buffers and uses LRU replacement policy. The disk block size and buffer pool block sizes are the same. You are given a routine int lru_block_in_position (int i) which returns the block_id of the block in the i-th position in the list of blocks managed by LRU. Assume position 0 is the hottest. You can repeatedly call this routine. How would you get the histogram you desire?
Hints and Answers
1. Simply do histogram [lru_block_in_position (b-1)] ++ at frequent intervals... The sampling frequency should be close to the disk I/O rate. It can be adjusted by remembering the last block seen in position b. If same, decrease frequency; if different, increase, with exponential decay etc. And of course, take care of overflows in the histogram.
Semaphores
1. Implement a multiple-reader-single-writer lock given a compare-and-swap instruction. Readers cannot overtake waiting writers.
Computer Architecture
1. Explain what is DMA?
2. What is pipelining?
3. What are superscalar machines and vliw machines?
4. What is cache?
5. What is cache coherency and how is it eliminated?
6. What is write back and write through caches?
7. What are different pipelining hazards and how are they eliminated.
8. What are different stages of a pipe?
9. Explain more about branch prediction in controlling the control hazards
10. Give examples of data hazards with pseudo codes.
11. How do you calculate the number of sets given its way and size in a cache?
12. How is a block found in a cache?
13. Scoreboard analysis.
14. What is miss penalty and give your own ideas to eliminate it.
15. How do you improve the cache performance.
16. Different addressing modes.
17. Computer arithmetic with two's complements.
18. About hardware and software interrupts.
19. What is bus contention and how do you eliminate it.
20. What is aliasing?
21) What is the difference between a latch and a flip flop?
22) What is the race around condition? How can it be overcome?
23) What is the purpose of cache? How is it used?
24) What are the types of memory management?
Kiran Bondalapati Homepage
Microsoft Interview Report for Software Engineer / Developer by jrk | CareerCup
Question in speech recognition. Design and implement an algorithm to match formants on spectrograms, subject to non-linear transformation of time and frequency.
Sunday, April 10, 2011
四十条成功人生座右铭 (04102011)
１．不要看我失去什么，只看我还拥有什么？
２．当你跌到谷底时，那正表示，你只能往上，不能往下！
３．不同的信念，决定不同的命运！
４．成功这件事，自己才是老板！
５．暗自伤心，不如立即行动．
６．挫折时，要像大树一样，被砍了，还能再长；也要像杂草一样，虽让人践踏，但还能勇敢地活下去．
７．不要以为还存在，就永远不会失去．
８．随随便便浪费的时间，再也不能赢回来．
９．成功是优点的发挥，失败，是缺点的积累．
１0．生命是罐头，胆量是开罐器．
１1．只要有斗志，不怕没战场．
１2．人没有选择的出生环境的权利，却有改变生活环境的权利．
１3．人不冒险，枉为一生．
１4．最困难的时候，就是距离成功不远了．
１5．再多一点努力，就多一点成功．
１6．除非想成为一流，否则就是二流．
１7．在你内心深处，还有无穷的潜力，有一天当你回首看时，你就会知道这绝对是真的．
1 8．成功，往往住在失败的隔壁！
1 9 生命不是要超越别人，而是要超越自己．
2 0．命运是那些懦弱和认命的人发明的！
２1．人生最大的喜悦是每个人都说你做不到，你却完成它了！
２2．世界上大部分的事情，都是觉得不太舒服的人做出来的．
２3．昨天是失效的支票，明天是未兑现的支票，今天才是现金．
２4．一直割舍不下一件事，永远成不了!
２5．扫地，要连心地一起扫！
２6．不为模糊不清的未来担忧，只为清清楚楚的现在努力．
２7．当你停止尝试时，就是失败的时候．
２8．心灵激情不在，就可能被打败．
２9．凡事不要说＂我不会＂或＂不可能＂，因为你根本还没有去做！
３0．成功不是靠梦想和希望，而是靠努力和实践．
３1．只有在天空最暗的时候，才可以看到天上的星星．
３2．上帝说：你要什么便取什么，但是要付出相当的代价．
３3．现在站在什么地方不重要，重要的是你往什么方向移动？
３4．宁可辛苦一阵子，不要苦一辈子．
３5．为成功找方法，不为失败找借口．
３6．敢先不要脸，就会有头有脸！
３7．垃圾桶哲学：别人不要做的事，我拣来做！
３8．不一定要做最大的，但要做最好的．
３9．死的方式由上帝决定，活的方式由自己决定！
４0．成功是动词，不是名词！
来源 http://hi.baidu.com/junnannet/blog/item/3db38d3d96af7ec59e3d6279.html
更多精彩
按创业实战各阶段阅读：
创业萌芽阶段(适合有志创业的朋友)
http://www.cyease.com.cn/a/480.htm
创业准备阶段
http://www.cyease.com.cn/a/479.htm
创业进行阶段
http://www.cyease.com.cn/a/478.htm
专题
如何白手起家 http://www.cyease.com.cn/a/773.shtm
如何找商机 http://www.cyease.com.cn/g/10001.htm
奥运中各行各业的商机 http://www.cyease.com.cn/la/t1s104.htm
网络营销与网络淘金指南 http://www.cyease.com.cn/la/t1s105.htm
IT创业专题 http://www.cyease.com.cn/a/443.htm
大学生创业专题http://www.cyease.com.cn/a/3992.shtml
个人理财指南 http://www.cyease.com.cn/a/709.shtml
人生励志系列 http://www.cyease.com.cn/la/t1s2.htm
２．当你跌到谷底时，那正表示，你只能往上，不能往下！
３．不同的信念，决定不同的命运！
４．成功这件事，自己才是老板！
５．暗自伤心，不如立即行动．
６．挫折时，要像大树一样，被砍了，还能再长；也要像杂草一样，虽让人践踏，但还能勇敢地活下去．
７．不要以为还存在，就永远不会失去．
８．随随便便浪费的时间，再也不能赢回来．
９．成功是优点的发挥，失败，是缺点的积累．
１0．生命是罐头，胆量是开罐器．
１1．只要有斗志，不怕没战场．
１2．人没有选择的出生环境的权利，却有改变生活环境的权利．
１3．人不冒险，枉为一生．
１4．最困难的时候，就是距离成功不远了．
１5．再多一点努力，就多一点成功．
１6．除非想成为一流，否则就是二流．
１7．在你内心深处，还有无穷的潜力，有一天当你回首看时，你就会知道这绝对是真的．
1 8．成功，往往住在失败的隔壁！
1 9 生命不是要超越别人，而是要超越自己．
2 0．命运是那些懦弱和认命的人发明的！
２1．人生最大的喜悦是每个人都说你做不到，你却完成它了！
２2．世界上大部分的事情，都是觉得不太舒服的人做出来的．
２3．昨天是失效的支票，明天是未兑现的支票，今天才是现金．
２4．一直割舍不下一件事，永远成不了!
２5．扫地，要连心地一起扫！
２6．不为模糊不清的未来担忧，只为清清楚楚的现在努力．
２7．当你停止尝试时，就是失败的时候．
２8．心灵激情不在，就可能被打败．
２9．凡事不要说＂我不会＂或＂不可能＂，因为你根本还没有去做！
３0．成功不是靠梦想和希望，而是靠努力和实践．
３1．只有在天空最暗的时候，才可以看到天上的星星．
３2．上帝说：你要什么便取什么，但是要付出相当的代价．
３3．现在站在什么地方不重要，重要的是你往什么方向移动？
３4．宁可辛苦一阵子，不要苦一辈子．
３5．为成功找方法，不为失败找借口．
３6．敢先不要脸，就会有头有脸！
３7．垃圾桶哲学：别人不要做的事，我拣来做！
３8．不一定要做最大的，但要做最好的．
３9．死的方式由上帝决定，活的方式由自己决定！
４0．成功是动词，不是名词！
来源 http://hi.baidu.com/junnannet/blog/item/3db38d3d96af7ec59e3d6279.html
更多精彩
按创业实战各阶段阅读：
创业萌芽阶段(适合有志创业的朋友)
http://www.cyease.com.cn/a/480.htm
创业准备阶段
http://www.cyease.com.cn/a/479.htm
创业进行阶段
http://www.cyease.com.cn/a/478.htm
专题
如何白手起家 http://www.cyease.com.cn/a/773.shtm
如何找商机 http://www.cyease.com.cn/g/10001.htm
奥运中各行各业的商机 http://www.cyease.com.cn/la/t1s104.htm
网络营销与网络淘金指南 http://www.cyease.com.cn/la/t1s105.htm
IT创业专题 http://www.cyease.com.cn/a/443.htm
大学生创业专题http://www.cyease.com.cn/a/3992.shtml
个人理财指南 http://www.cyease.com.cn/a/709.shtml
人生励志系列 http://www.cyease.com.cn/la/t1s2.htm
Sunday, April 3, 2011
陈安之超级成功学经典语录大全
陈安之超级成功学经典语录大全
陈安之成功学之行销法则
1.要随时想象，成功者每天在想什么？每天在做什么？
2.要成功，就要把成功者的想法和行为复制到自己行动中。
3.成功＝知识＋人脉。
4.知识占成功要素的百分之三十，人际关系占成功要素的百分之七十。 5.不断的补充知识是你获得成功的前提。
6.别只看到别人成功的结果，也要经常思考别人成功的原因。
7.所有成功的人都是善于阅读的人，所有领导者也都是阅读者。
8.多懂顾客喜欢的一种知识，你就多一次成功的机会。
9.要成功你就要具备一周工作七天，每一天工作24小时的意识。
10.掌握的知识越多，你就越能和顾客成为知己，找到共鸣的话题。
11.亚洲首富平均每天阅读5本书，一年阅读2000本书籍。
12.世界最聪明的推销员，9岁就读完了百科全书。
13.世界首富一开始就以最直接的人际关系与世界最大的企业做了生意。
14.世界汽车推销冠军秘诀之一就是大量的逢人就派名片。（结交人际关系要主动出击）
15. 在任何时间，任何地点你都要介绍自己，推销自己。
16.每天晚上，你都要把今天交谈过的每一个人的名字和内容复习整理一遍。
17.只要凡事认真，你的业绩就会好起来。（业绩好的公司就是比较认真）
18.提高行销业绩的关键，就是你要制订出每天要完成的量化目标。 （行销要成功要学会电话行销）
19.每天你要完成100个陌生顾客的拜访数量，并且要站着打电话。
20.每一份私下努力的结果，你都会获得倍增的回报，最终都会在公众面前表现出来。
21.要想获得什么，就看你付出的是什么。
22.要想超过谁，你就要比他更努力四倍（要具体和量化）（顾客不只买产品，他更买你做事认真的态度．）。
23.获得顾客上门推荐的机会，你就成功了一半。
24.即使顾客不买产品，你仍然要给他提供咨询和售前服务。
25.你先为顾客考虑，顾客才为你考虑。
26.顾客往往购买的是你的服务态度。
27.推销员推销自己比推销产品更重要。
28.只有当顾客真正喜欢你相信你之后，才会开始购买你的产品。（成功的秘决：认真＋准时）
29.推销冠军的习惯不仅要准时，还必须提前做准备。
30.在见顾客前5分钟，照着镜子对自己夸奖一番。
31.任何地点，任何时候你都言行一致，是给人信心的保证。
32.没有面对客户时，你也要百分之百的对客户尊敬。
33.成功行销就是永不放弃，放弃者不可能成功。
34.顾客不仅买产品，更买你的服务精神和服务态度。
35.顾客反对意见太多，只代表一件事，那就是他不相信你，他不喜欢你。
36.从语言速度和肢体动作上去模仿对方、去配合对方是你超速赢得信任的秘方。
类型：１，视觉型（讲话声音快，速度快，眼珠不断的转动）
２，听觉型（讲话声音稍小一点，有时眼睛不在看你）
３，触觉型（讲话想了老半天才讲出来的人．．）
陈安之成功学之人才法则
1：世界上3％的人有强烈的成功动机。
2：要成功，就要跟成功者在一起。
3：成功者，凡事主动出击。
4：要成功就不要有借口，要借口就难以成功。
5：要研究成功者的想法、策略和行为习惯。
6：成功者是比对手多做一下，坚持到底的人。
7：成功者拥有强烈坚定的信念。
8：成功者“热爱痛苦”。
9：“过去不等于未来！”
10：“没有失败——只有暂时停止成功！”
11：“假如我没有得到我要的，我即将得到更好的！”
12：“成功者愿意做一般人不愿意做的事”
13：“成功者做一般人不敢做、做不到的事情”
14：“凡事以最短的时间，采取最大量的行动”
15：“成功者累积知识和人脉的质和量”
16：任何成功者，都靠投资脑袋赚钱。
17：成功者拥有一流的态度、技巧和能力。
18：成功的态度决定一切。 态度占100％。
19：技巧和能力决定胜负。 他们也占100％。
20：态度好的人，赚钱的机会比较多。
21：顾客买的是服务态度和工作精神。
22：当你成为行业第一名时，财富和荣誉挡都挡不住。
23：成功的5大步骤：
1、要有明确的目标
2、要有详细的计划
3、要立即采取行动。
4、要修正你的行动
5、要坚持到底。
24：只有检讨才是成功之母。
（失败不是成功之母，检讨才是成功之母）
25：成功的第一步：天天看“梦想版”
26：让成功的梦想视觉化，反复加深印象。
27：订目标——做计划——大量行动
28：反复认为自己是什么，就一定会成为什么。
29：当有人说你“疯”了的时候，可能你要成功了。
30：要想成为什么人——就要和什么人在一起。
31：只有充分放松，才能有力地出击。
32：目标要实现，第一要专注、第二要重复。
33：每天手写核心目标10遍以上。
34：成功是很简单很容易的事情——只要方法正确。
35：成功者永不放弃，放弃者绝不成功！
36：坚持到底，决不放弃——是成功的秘诀、保证。
一、人才的竞争是决定成败的关键。
二、看企业有什么样的人才就能衡量出第几流的企业。
三、领导的能力是选对人而不是训练人。
四、选择人才首先要列出理想人才的具体标准。
五、人才的态度、能力和忠诚度，三者缺一不可。
六、企业要成功就要多录用有成功经验的人。
七、选有成功经验的总教练就能带出成功的团队。
八、不要录用以赚钱为第一动机的人。（没有忠诚度就无法建立团队） 九、录取一定要赢并有方法成为第一的人。
十、录取每一个人以保证团队的向心力为标准。
十一、从小细节小工作来衡量一个人能否做大事。
十二、企业不是品质、价格、服务的竞争，而是人才的竞争。
十三、选择人才心太软就是对团队的成败不负责任。
十四、属于”资产”的人才要让他们增值，属于”负债”的就要除恶。（定期淘汰法管理人才）
十五、市场以结果论英雄，以结果为导向。
十六、总裁第一件最重要的工作是“思考”。（失败不是成功之母，检讨才是成功之母）
十七、成功就是简单的事情不断重复地做。
十八、检讨才是成功之母，改进缺点，比发挥优点更重要。
十九、每天要求员工进步百分之一。
二十、每天分析哪里做对，哪里做错了，明天如何做得更好。
二十一、总裁第二件最重要的工作就是“招兵买马”选对人。
二十二、最好的人才是最贵的，但也是免费的。
二十三、有潜力的企业吸引优秀的人才，优秀人才又吸引优秀人才一起发展。
二十四、要为优秀的人才创造归属感和独当一面的机会。
二十五、总裁第三件最重要的工作就是“推销”。
二十六、总裁要亲临第一线做“推销”。
二十七、研究成败的规律才能守住成功。
二十八、领导是用行动领导，不是口头领导。
二十九、总裁第四件最重要的工作就是“沟通员工”。
三十、总裁第五件最重要的工作就是“倾听顾客”。
三十一、总裁第六件最重要的工作就是“关心部属”。
三十二、人事管理第一要抓心态管理。
三十三、总裁第七件最重要的工作就是“奖励”。
三十四、总裁第八件最重要的工作就是“激励”（团队）。
三十五、领导者不是领导利润。而是领导使命、责任感、团队精神和团队目标。
三十六、严格要求自己和下属才是对团队对社会负责。
01——要创业你就要做好亏钱或赢钱的准备。
02——学习世界首富的思考模式才可实现倍增的业绩。
03——超速创业成功的关键是眼光要好。
04——要知道不是所有的行业都赚一样多的钱。
05——创业前一定要先对你所从事的行业有所评估。
06——掌握未来趋势比掌握资讯更重要。
07——掌握趋势不如掌握最大的趋势。
08——与其同“马”赛跑不如骑在马上才能“马上成功”。
09——成功的速度取决于我们是否拥有最好的工具。
10——找最好的“产品马”来经营是老版的责任。
11——找最优秀的人为你工作才能马上成功。
12——与人竞争不如与人合作。技术好，经验丰富不如坐好的车子，骑一匹好的马！
13——选择竞争对手少的行业意味着不战而胜。
14——三大眼光：大的趋势、大的市场、少的竞争对手。
15——做未来成长空间大的行业。
16——产品销量大是致富的关键。
17——市场需求大、市场大、是量大的前提。
18——产品卖不出去的原因在于产品的品质和价格。
19——确保你的产品品质是同等级同价格当中最好的。
20——要定出消费者心里的承受价格而不是一味求高或求低。
21——不只做售后服务更要做售前服务。
22——顾客不买产品时依然要给顾客提供资讯。
23——企业最大的成本是没有经过训练的业务员。
24——用对的方法来销售产品是公司业绩提升的保证。
25——用公司第一名的营销代表做业务培训胜过于让他亲自做业务。
26——产品通路多销量才会大。
27——宣传、宣传、再宣传。
28——世界上没有完美的个人只有完美的团队。
29——授权不等于弃权，授权之后更要加以监督。
30——要从事走动式管理。
31——没有正确的督导和管理等于浪费人才。
32——一流的人才是无价的。
33——世界第一名的总裁每天会亲临第一线。
34——成功等于每天进步百分之一。
35——过去不等于未来，没有失败，只有暂时停止成功。
36——坚持等于成功放弃者绝不成功。
陈安之成功学之行销法则
1.要随时想象，成功者每天在想什么？每天在做什么？
2.要成功，就要把成功者的想法和行为复制到自己行动中。
3.成功＝知识＋人脉。
4.知识占成功要素的百分之三十，人际关系占成功要素的百分之七十。 5.不断的补充知识是你获得成功的前提。
6.别只看到别人成功的结果，也要经常思考别人成功的原因。
7.所有成功的人都是善于阅读的人，所有领导者也都是阅读者。
8.多懂顾客喜欢的一种知识，你就多一次成功的机会。
9.要成功你就要具备一周工作七天，每一天工作24小时的意识。
10.掌握的知识越多，你就越能和顾客成为知己，找到共鸣的话题。
11.亚洲首富平均每天阅读5本书，一年阅读2000本书籍。
12.世界最聪明的推销员，9岁就读完了百科全书。
13.世界首富一开始就以最直接的人际关系与世界最大的企业做了生意。
14.世界汽车推销冠军秘诀之一就是大量的逢人就派名片。（结交人际关系要主动出击）
15. 在任何时间，任何地点你都要介绍自己，推销自己。
16.每天晚上，你都要把今天交谈过的每一个人的名字和内容复习整理一遍。
17.只要凡事认真，你的业绩就会好起来。（业绩好的公司就是比较认真）
18.提高行销业绩的关键，就是你要制订出每天要完成的量化目标。 （行销要成功要学会电话行销）
19.每天你要完成100个陌生顾客的拜访数量，并且要站着打电话。
20.每一份私下努力的结果，你都会获得倍增的回报，最终都会在公众面前表现出来。
21.要想获得什么，就看你付出的是什么。
22.要想超过谁，你就要比他更努力四倍（要具体和量化）（顾客不只买产品，他更买你做事认真的态度．）。
23.获得顾客上门推荐的机会，你就成功了一半。
24.即使顾客不买产品，你仍然要给他提供咨询和售前服务。
25.你先为顾客考虑，顾客才为你考虑。
26.顾客往往购买的是你的服务态度。
27.推销员推销自己比推销产品更重要。
28.只有当顾客真正喜欢你相信你之后，才会开始购买你的产品。（成功的秘决：认真＋准时）
29.推销冠军的习惯不仅要准时，还必须提前做准备。
30.在见顾客前5分钟，照着镜子对自己夸奖一番。
31.任何地点，任何时候你都言行一致，是给人信心的保证。
32.没有面对客户时，你也要百分之百的对客户尊敬。
33.成功行销就是永不放弃，放弃者不可能成功。
34.顾客不仅买产品，更买你的服务精神和服务态度。
35.顾客反对意见太多，只代表一件事，那就是他不相信你，他不喜欢你。
36.从语言速度和肢体动作上去模仿对方、去配合对方是你超速赢得信任的秘方。
类型：１，视觉型（讲话声音快，速度快，眼珠不断的转动）
２，听觉型（讲话声音稍小一点，有时眼睛不在看你）
３，触觉型（讲话想了老半天才讲出来的人．．）
陈安之成功学之人才法则
1：世界上3％的人有强烈的成功动机。
2：要成功，就要跟成功者在一起。
3：成功者，凡事主动出击。
4：要成功就不要有借口，要借口就难以成功。
5：要研究成功者的想法、策略和行为习惯。
6：成功者是比对手多做一下，坚持到底的人。
7：成功者拥有强烈坚定的信念。
8：成功者“热爱痛苦”。
9：“过去不等于未来！”
10：“没有失败——只有暂时停止成功！”
11：“假如我没有得到我要的，我即将得到更好的！”
12：“成功者愿意做一般人不愿意做的事”
13：“成功者做一般人不敢做、做不到的事情”
14：“凡事以最短的时间，采取最大量的行动”
15：“成功者累积知识和人脉的质和量”
16：任何成功者，都靠投资脑袋赚钱。
17：成功者拥有一流的态度、技巧和能力。
18：成功的态度决定一切。 态度占100％。
19：技巧和能力决定胜负。 他们也占100％。
20：态度好的人，赚钱的机会比较多。
21：顾客买的是服务态度和工作精神。
22：当你成为行业第一名时，财富和荣誉挡都挡不住。
23：成功的5大步骤：
1、要有明确的目标
2、要有详细的计划
3、要立即采取行动。
4、要修正你的行动
5、要坚持到底。
24：只有检讨才是成功之母。
（失败不是成功之母，检讨才是成功之母）
25：成功的第一步：天天看“梦想版”
26：让成功的梦想视觉化，反复加深印象。
27：订目标——做计划——大量行动
28：反复认为自己是什么，就一定会成为什么。
29：当有人说你“疯”了的时候，可能你要成功了。
30：要想成为什么人——就要和什么人在一起。
31：只有充分放松，才能有力地出击。
32：目标要实现，第一要专注、第二要重复。
33：每天手写核心目标10遍以上。
34：成功是很简单很容易的事情——只要方法正确。
35：成功者永不放弃，放弃者绝不成功！
36：坚持到底，决不放弃——是成功的秘诀、保证。
一、人才的竞争是决定成败的关键。
二、看企业有什么样的人才就能衡量出第几流的企业。
三、领导的能力是选对人而不是训练人。
四、选择人才首先要列出理想人才的具体标准。
五、人才的态度、能力和忠诚度，三者缺一不可。
六、企业要成功就要多录用有成功经验的人。
七、选有成功经验的总教练就能带出成功的团队。
八、不要录用以赚钱为第一动机的人。（没有忠诚度就无法建立团队） 九、录取一定要赢并有方法成为第一的人。
十、录取每一个人以保证团队的向心力为标准。
十一、从小细节小工作来衡量一个人能否做大事。
十二、企业不是品质、价格、服务的竞争，而是人才的竞争。
十三、选择人才心太软就是对团队的成败不负责任。
十四、属于”资产”的人才要让他们增值，属于”负债”的就要除恶。（定期淘汰法管理人才）
十五、市场以结果论英雄，以结果为导向。
十六、总裁第一件最重要的工作是“思考”。（失败不是成功之母，检讨才是成功之母）
十七、成功就是简单的事情不断重复地做。
十八、检讨才是成功之母，改进缺点，比发挥优点更重要。
十九、每天要求员工进步百分之一。
二十、每天分析哪里做对，哪里做错了，明天如何做得更好。
二十一、总裁第二件最重要的工作就是“招兵买马”选对人。
二十二、最好的人才是最贵的，但也是免费的。
二十三、有潜力的企业吸引优秀的人才，优秀人才又吸引优秀人才一起发展。
二十四、要为优秀的人才创造归属感和独当一面的机会。
二十五、总裁第三件最重要的工作就是“推销”。
二十六、总裁要亲临第一线做“推销”。
二十七、研究成败的规律才能守住成功。
二十八、领导是用行动领导，不是口头领导。
二十九、总裁第四件最重要的工作就是“沟通员工”。
三十、总裁第五件最重要的工作就是“倾听顾客”。
三十一、总裁第六件最重要的工作就是“关心部属”。
三十二、人事管理第一要抓心态管理。
三十三、总裁第七件最重要的工作就是“奖励”。
三十四、总裁第八件最重要的工作就是“激励”（团队）。
三十五、领导者不是领导利润。而是领导使命、责任感、团队精神和团队目标。
三十六、严格要求自己和下属才是对团队对社会负责。
01——要创业你就要做好亏钱或赢钱的准备。
02——学习世界首富的思考模式才可实现倍增的业绩。
03——超速创业成功的关键是眼光要好。
04——要知道不是所有的行业都赚一样多的钱。
05——创业前一定要先对你所从事的行业有所评估。
06——掌握未来趋势比掌握资讯更重要。
07——掌握趋势不如掌握最大的趋势。
08——与其同“马”赛跑不如骑在马上才能“马上成功”。
09——成功的速度取决于我们是否拥有最好的工具。
10——找最好的“产品马”来经营是老版的责任。
11——找最优秀的人为你工作才能马上成功。
12——与人竞争不如与人合作。技术好，经验丰富不如坐好的车子，骑一匹好的马！
13——选择竞争对手少的行业意味着不战而胜。
14——三大眼光：大的趋势、大的市场、少的竞争对手。
15——做未来成长空间大的行业。
16——产品销量大是致富的关键。
17——市场需求大、市场大、是量大的前提。
18——产品卖不出去的原因在于产品的品质和价格。
19——确保你的产品品质是同等级同价格当中最好的。
20——要定出消费者心里的承受价格而不是一味求高或求低。
21——不只做售后服务更要做售前服务。
22——顾客不买产品时依然要给顾客提供资讯。
23——企业最大的成本是没有经过训练的业务员。
24——用对的方法来销售产品是公司业绩提升的保证。
25——用公司第一名的营销代表做业务培训胜过于让他亲自做业务。
26——产品通路多销量才会大。
27——宣传、宣传、再宣传。
28——世界上没有完美的个人只有完美的团队。
29——授权不等于弃权，授权之后更要加以监督。
30——要从事走动式管理。
31——没有正确的督导和管理等于浪费人才。
32——一流的人才是无价的。
33——世界第一名的总裁每天会亲临第一线。
34——成功等于每天进步百分之一。
35——过去不等于未来，没有失败，只有暂时停止成功。
36——坚持等于成功放弃者绝不成功。
成功语录----陈安之
别再自己摸索，问路才不会迷路。
过去不等于未来；没有失败，只有暂时停止成功；采取更大量的行动。
相信教练的话一定有道理。
远大的目标非常重要，一定要有成功的企图心，而且越大越好。
成功的秘诀是努力，所以的第一名都是练出来的。HARD WORK！
宁愿辛苦一阵子，不要辛苦一辈子。
成功者怎么做，我就怎么做。
成功需要改变，用新的方法改变过去的结果。
联系时厉害，比赛时就厉害。
问题永远在自己身上。
积极向上是所以成功者的特质。
要成功，先发疯，头脑简单向前冲。
承诺是走向成功的必由之路；用公众承诺的力量逼自己成功。
成功等于目标，等于每天进步1％，等于全方位。
只要每天进步就开始进步了。
没有退路时潜能就发挥出来了。
决定可以克服不可能的事情。
每天只看目标，别老想障碍。
用心观察成功者，别老是关注失败者。
付出才会杰出；为别人创造价值，别人才愿意和你交往。
只向最顶端的人学习，只和最棒的人交往，只做最棒的人做的事。
书本也是好老师，活用才能成功。
行动才能成功，教练改变人生。
过去不等于未来,没有失败,只有暂时停止成功.
要成功,需要跟成功者在一起.
每一分私下的努力,都会有倍增的回收,在公众面前被表扬出来.
要成功,不要与马赛跑,要骑在马上,马上成功.
要跟成功者有同样的结果,就必须采取同样的行动.
成功就是简单的事情不断地重复做.
成功者不是比你聪明,只是在最短的时间采取最大的行动.
成功者,做别人不愿意做的事情,别人不敢做的事情,做不到的事情.
只有全力以赴,梦想才能起飞.
领导力不是训练人,是选对人.
一个公司最大的成本是没有训练过的业务员.
最好的人才是免费的,因为他赚取的利润早就把他的薪水给盖住了.
顾客不是买产品,他更买做事认真的态度、服务态度和服务精神.
世界级的竟争,一律以结果为导向,市场以结果论英雄
过去不等于未来；没有失败，只有暂时停止成功；采取更大量的行动。
相信教练的话一定有道理。
远大的目标非常重要，一定要有成功的企图心，而且越大越好。
成功的秘诀是努力，所以的第一名都是练出来的。HARD WORK！
宁愿辛苦一阵子，不要辛苦一辈子。
成功者怎么做，我就怎么做。
成功需要改变，用新的方法改变过去的结果。
联系时厉害，比赛时就厉害。
问题永远在自己身上。
积极向上是所以成功者的特质。
要成功，先发疯，头脑简单向前冲。
承诺是走向成功的必由之路；用公众承诺的力量逼自己成功。
成功等于目标，等于每天进步1％，等于全方位。
只要每天进步就开始进步了。
没有退路时潜能就发挥出来了。
决定可以克服不可能的事情。
每天只看目标，别老想障碍。
用心观察成功者，别老是关注失败者。
付出才会杰出；为别人创造价值，别人才愿意和你交往。
只向最顶端的人学习，只和最棒的人交往，只做最棒的人做的事。
书本也是好老师，活用才能成功。
行动才能成功，教练改变人生。
过去不等于未来,没有失败,只有暂时停止成功.
要成功,需要跟成功者在一起.
每一分私下的努力,都会有倍增的回收,在公众面前被表扬出来.
要成功,不要与马赛跑,要骑在马上,马上成功.
要跟成功者有同样的结果,就必须采取同样的行动.
成功就是简单的事情不断地重复做.
成功者不是比你聪明,只是在最短的时间采取最大的行动.
成功者,做别人不愿意做的事情,别人不敢做的事情,做不到的事情.
只有全力以赴,梦想才能起飞.
领导力不是训练人,是选对人.
一个公司最大的成本是没有训练过的业务员.
最好的人才是免费的,因为他赚取的利润早就把他的薪水给盖住了.
顾客不是买产品,他更买做事认真的态度、服务态度和服务精神.
世界级的竟争,一律以结果为导向,市场以结果论英雄
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