인터넷의 구글 입사 문제라는...

실제 면접에는 없다고 하는데 진위 여부는 따져봐야겠지. 

1. 당신은 똑같은 크기의 공을 8개 갖고 있습니다. 그 중에 7개는 같은 무게지만 한 개는 다른 것에 비해 살짝 무겁습니다. 저울을 2번만 사용해 살짝 무거운 공 하나를 찾아내려면 어떻게 해야 할까요?

첨에 3개씩 달면 됨. 

2. 시계를 보니 3시 15분입니다. 시침과 분침 사이의 각도는?

360/12 * 3

360/60 * 15

0이 아니라면  그 시계의 고장난 만큼.

3. 고속도로에서 30분 동안 승용차가 존재할 확률이 0.95라고 할 때 10분 동안 존재할 확률은 얼마가 될까요? (확률은 일정하다고 가정합니다.)

30분 존재 = (10분 동안 존재할 확률)^3

0.98...

4. 어느 나라의 사람들은 태어나는 아이 모두 남자아이만을 원합니다. 때문에 모든 가정이 남자아이가 태어날 때까지 계속 아이를 낳았습니다. 이 나라의 남녀 인구 비율은 어떻게 될까요?

다른 세대 간 결혼하지 않고, 근친X, 1부 1처제에 바람을 피자 않을 일 경우  1:1

남:녀가 되지 않으면 자식을 낳지 못하기 때문.

5. 시계의 시침과 분침은 하루에 몇 번 겹쳐질까요?

24번. 시침 두께에 따라 23번 

6. 당신의 8살된 조카에게 '데이터베이스'에 관해 세 개의 문장으로 설명해 보세요.

여름 날 잘 포장된 아이스크림을 꺼내먹는 냉장고.

놀고나서 정리하고 다시 꺼내 놀 수 있는 자기 소유의 장난감 정리함.

너의 장난감과 합쳐질 수 있는 다른 사람의 레고 세트 

7. 전세계 피아노 조율사는 몇 명일까요?

0< 피아노 조율사 < 피아노 대수 

8. 어떤 마을에 100쌍의 부부가 있습니다. 남편들은 전원 바람을 피고 있습니다. 아내들은 모두 자신의 남편 이외의 남자들이 바람을 피고 있다고 생각합니다. 이 마을의 정해진 법률은 외도와 간통을 허락하지 않습니다. 또한 누구든 자신의 남편이 바람을 피고 있다는 사실을 알게되면 즉시 자신의 남편을 죽이는 규율이 있습니다. 이 마을의 여성들은 규율을 어기지 못합니다. 어느 날 마을의 왕비가 말했습니다. 이 마을에는 외도하고 있는 남자가 적어도 한 명은 있다. 자, 앞으로 이 마을에는 무슨 일이 벌어질까요?

1. 아무일도 없다. 왕비의 말은 모든 아내들의 생각에 포함됨.

2. 모두 죽는다. 모두 왕비랑 바람을 폈다. (아내들이 자신의 남편만은 바람을 안 핀다고 생각한 것은 자신도 다른 사람과 바람을 피지 않았기 때문)

2-1. 왕이 왕비를 사랑한다면 규율을 없앨 것이기 때문에 아무일도 없다.

2-2. 남자가 모두 죽으면 나라가 위태롭기 때문에 아무일도 없을 것이다.

결국 아무일도 없다.

이 수학문제를 풀어야 입사지원 된다?

지디넷코리아]실리콘밸리 중심가 101번 고속도로가 통과하는 곳에 최근 광고판 하나가 달렸다. 광고판에는 아무런 설명없이 수학문제 하나만 덩그러니 담겨있다.

검색업계의 강자 구글이 아무런 표시도, 설명도 없는 광고판을 세운 이유는 이 문제를 풀 수 있는 수학적 두뇌를 가진 사람을 골라 입사 기회를 주기 위해서라고 한다. 수학자 폴 아도스의 유명한 “수학자란 커피를 정리로 변환시키는 장치”라는 말을 연상시키는 채용방법이다.
광고판에는 ‘{자연대수 e를 풀어서 쓸 때 처음 발견되는 10자리수 솟수(first 10-digit prime found in consecutive digits of e)}.com’이라고 적혀있다. 답은 7427466391이다. 이 문제를 풀어 7427466391.com으로 접속해보면 2번째 관문인 다른 문제가 나오는데, 여기에도 구글이라는 이름은 없다.

2단계 문제까지 풀면 비로소 구글 연구개발부서인 구글랩 페이지로 연결되며, “구글을 키워나가면서 우리가 배운 점 한가지는 우리가 찾고자 하는 상대방 역시 우리를 찾고 있을 때, 그 사람을 더 쉽게 찾게 된다는 것이다. 우리는 세계 최고의 엔지니어를 찾고 있고, 당신은 여기에 와있다”라는 환영 메시지를 볼 수 있다.

메시지는 “짐작하겠지만 우리는 엄청난 량의 이력서를 매일같이 받고 있기 때문에 이러한 절차를 이용해 ‘신호대 잡음비’를 개선하려 하는 것”이라는 말로 이어진다.

올해 말 27억달러 규모의 IPO를 준비중인 구글은 깐깐한 채용 과정으로 유명하다. 회사 설립 첫날부터 3월 31일 현재 직원수 1907명에 이르기까지 구글은 자사만의 채용 기준을 엄격히 준수해왔다.

팔로알토 차고에서 운영되던 초창기에 입사한 한 직원은 “면접 볼 때 세르게이 브린과 래리 페이지(이상 구글 공동설립인)의 책상 위에는 8권의 채용관련 서적이 쌓여 있었다”고 말했다.

구글 직원들은 많은 면접 단계를 거쳤으며, 종종 수학이나 사업전략에 대한 테스트도 요구받았다고 한다. 채용조건은 이와같은 단계가 끝난 후에나 알 수 있었다. 최근 2년 동안에는 우수 인력을 영입하기 위해 프로그래밍 대회를 개최하기도 했다.

구글이 시행한 또한가지 독특한 채용방법은 검색결과 페이지의 광고 링크를 이용한 것이다. 예를 들면 아마존의 검색기술 연구팀인 A9의 팀장 우디 맨버(Udi Manber)를 구글에서 검색하면 검색결과 오른쪽 스폰서 링크에 ‘구글에서 일하세요’라는 문구가 뜨고, 구글 구인 페이지로 연결하는 링크가 나타난다.

한편 현재 구글에서 근무하는 컴퓨터 엔지니어들은 대부분 스탠포드 대학 컴퓨터과학도 출신인 것으로 알려졌다.

이번 수학문제 광고판은 산타클라라 방향에서 롤스톤으로 빠지는 길 근처에 세워졌다. 이 회사 관계자는 상황에 따라 광고판을 더 늘릴 수도 있다고 밝혔다. @

구글입사 문제 맞네.

http://www.businessinsider.com/answers-to-15-google-interview-questions-that-will-make-you-feel-stupid-2009-11#how-many-golf-balls-can-fit-in-a-school-bus-1

찾아보니 답이 있네

나머지 모든 문제

40 Google Interview Questions

October 24th, 2009 by lewis

Here’s a list of 140 Google interview questions. Many of our clients have interviewed and received Google job offers. Contact us for a free 15 minute interview analysis before your Google interview.
UPDATE: We are now offering online classes on How to Ace the Google Software Engineering Interview and How to Ace the Google Product Manager Interview.

Link to Google interview questions for:

Product Marketing Manager

Product Manager

Software Engineer

Software Engineer in Test

Quantitative Compensation Analyst

Engineering Manager

AdWords Associate

Google Interview Questions: Product Marketing Manager

• Why do you want to join Google?
• What do you know about Google’s product and technology?
• If you are Product Manager for Google’s Adwords, how do you plan to market this?
• What would you say during an AdWords or AdSense product seminar?
• Who are Google’s competitors, and how does Google compete with them?
• Have you ever used Google’s products? Gmail?
• What’s a creative way of marketing Google’s brand name and product?
• If you are the product marketing manager for Google’s Gmail product, how do you plan to market it so as to achieve 100 million customers in 6 months?
• How much money you think Google makes daily from Gmail ads?
• Name a piece of technology you’ve read about recently. Now tell me your own creative execution for an ad for that product.
• Say an advertiser makes $0.10 every time someone clicks on their ad. Only 20% of people who visit the site click on their ad. How many people need to visit the site for the advertiser to make $20?
• Estimate the number of students who are college seniors, attend four-year schools, and graduate with a job in the United States every year.

Google Interview Questions: Product Manager

• How would you boost the GMail subscription base?
• What is the most efficient way to sort a million integers?
• How would you re-position Google’s offerings to counteract competitive threats from Microsoft?
• How many golf balls can fit in a school bus?
• You are shrunk to the height of a nickel and your mass is proportionally reduced so as to maintain your original density. You are then thrown into an empty glass blender. The blades will start moving in 60 seconds. What do you do?
• How much should you charge to wash all the windows in Seattle?
• How would you find out if a machine’s stack grows up or down in memory?
• Explain a database in three sentences to your eight-year-old nephew.
• How many times a day does a clock’s hands overlap?
• You have to get from point A to point B. You don’t know if you can get there. What would you do?
• Imagine you have a closet full of shirts. It’s very hard to find a shirt. So what can you do to organize your shirts for easy retrieval?
• Every man in a village of 100 married couples has cheated on his wife. Every wife in the village instantly knows when a man other than her husband has cheated, but does not know when her own husband has. The village has a law that does not allow for adultery. Any wife who can prove that her husband is unfaithful must kill him that very day. The women of the village would never disobey this law. One day, the queen of the village visits and announces that at least one husband has been unfaithful. What happens?
• In a country in which people only want boys, every family continues to have children until they have a boy. If they have a girl, they have another child. If they have a boy, they stop. What is the proportion of boys to girls in the country?
• If the probability of observing a car in 30 minutes on a highway is 0.95, what is the probability of observing a car in 10 minutes (assuming constant default probability)?
• If you look at a clock and the time is 3:15, what is the angle between the hour and the minute hands? (The answer to this is not zero!)
• Four people need to cross a rickety rope bridge to get back to their camp at night. Unfortunately, they only have one flashlight and it only has enough light left for seventeen minutes. The bridge is too dangerous to cross without a flashlight, and it’s only strong enough to support two people at any given time. Each of the campers walks at a different speed. One can cross the bridge in 1 minute, another in 2 minutes, the third in 5 minutes, and the slow poke takes 10 minutes to cross. How do the campers make it across in 17 minutes?
• You are at a party with a friend and 10 people are present including you and the friend. your friend makes you a wager that for every person you find that has the same birthday as you, you get $1; for every person he finds that does not have the same birthday as you, he gets $2. would you accept the wager?
• How many piano tuners are there in the entire world?
• You have eight balls all of the same size. 7 of them weigh the same, and one of them weighs slightly more. How can you find the ball that is heavier by using a balance and only two weighings?
• You have five pirates, ranked from 5 to 1 in descending order. The top pirate has the right to propose how 100 gold coins should be divided among them. But the others get to vote on his plan, and if fewer than half agree with him, he gets killed. How should he allocate the gold in order to maximize his share but live to enjoy it? (Hint: One pirate ends up with 98 percent of the gold.)
• You are given 2 eggs. You have access to a 100-story building. Eggs can be very hard or very fragile means it may break if dropped from the first floor or may not even break if dropped from 100th floor. Both eggs are identical. You need to figure out the highest floor of a 100-story building an egg can be dropped without breaking. The question is how many drops you need to make. You are allowed to break 2 eggs in the process.
• Describe a technical problem you had and how you solved it.
• How would you design a simple search engine?
• Design an evacuation plan for San Francisco.
• There’s a latency problem in South Africa. Diagnose it.
• What are three long term challenges facing Google?
• Name three non-Google websites that you visit often and like. What do you like about the user interface and design? Choose one of the three sites and comment on what new feature or project you would work on. How would you design it?
• If there is only one elevator in the building, how would you change the design? How about if there are only two elevators in the building?
• How many vacuum’s are made per year in USA?

Google Interview Questions: Software Engineer

• Why are manhole covers round?
• What is the difference between a mutex and a semaphore? Which one would you use to protect access to an increment operation?
• A man pushed his car to a hotel and lost his fortune. What happened?
• Explain the significance of “dead beef”.
• Write a C program which measures the the speed of a context switch on a UNIX/Linux system.
• Given a function which produces a random integer in the range 1 to 5, write a function which produces a random integer in the range 1 to 7.
• Describe the algorithm for a depth-first graph traversal.
• Design a class library for writing card games.
• You need to check that your friend, Bob, has your correct phone number, but you cannot ask him directly. You must write a the question on a card which and give it to Eve who will take the card to Bob and return the answer to you. What must you write on the card, besides the question, to ensure Bob can encode the message so that Eve cannot read your phone number?
• How are cookies passed in the HTTP protocol?
• Design the SQL database tables for a car rental database.
• Write a regular expression which matches a email address.
• Write a function f(a, b) which takes two character string arguments and returns a string containing only the characters found in both strings in the order of a. Write a version which is order N-squared and one which is order N.
• You are given a the source to a application which is crashing when run. After running it 10 times in a debugger, you find it never crashes in the same place. The application is single threaded, and uses only the C standard library. What programming errors could be causing this crash? How would you test each one?
• Explain how congestion control works in the TCP protocol.
• In Java, what is the difference between final, finally, and finalize?
• What is multithreaded programming? What is a deadlock?
• Write a function (with helper functions if needed) called to Excel that takes an excel column value (A,B,C,D…AA,AB,AC,… AAA..) and returns a corresponding integer value (A=1,B=2,… AA=26..).
• You have a stream of infinite queries (ie: real time Google search queries that people are entering). Describe how you would go about finding a good estimate of 1000 samples from this never ending set of data and then write code for it.
• Tree search algorithms. Write BFS and DFS code, explain run time and space requirements. Modify the code to handle trees with weighted edges and loops with BFS and DFS, make the code print out path to goal state.
• You are given a list of numbers. When you reach the end of the list you will come back to the beginning of the list (a circular list). Write the most efficient algorithm to find the minimum # in this list. Find any given # in the list. The numbers in the list are always increasing but you don’t know where the circular list begins, ie: 38, 40, 55, 89, 6, 13, 20, 23, 36.
• Describe the data structure that is used to manage memory. (stack)
• What’s the difference between local and global variables?
• If you have 1 million integers, how would you sort them efficiently? (modify a specific sorting algorithm to solve this)
• In Java, what is the difference between static, final, and const. (if you don’t know Java they will ask something similar for C or C++).
• Talk about your class projects or work projects (pick something easy)… then describe how you could make them more efficient (in terms of algorithms).
• Suppose you have an NxN matrix of positive and negative integers. Write some code that finds the sub-matrix with the maximum sum of its elements.
• Write some code to reverse a string.
• Implement division (without using the divide operator, obviously).
• Write some code to find all permutations of the letters in a particular string.
• What method would you use to look up a word in a dictionary?
• Imagine you have a closet full of shirts. It’s very hard to find a shirt. So what can you do to organize your shirts for easy retrieval?
• You have eight balls all of the same size. 7 of them weigh the same, and one of them weighs slightly more. How can you fine the ball that is heavier by using a balance and only two weighings?
• What is the C-language command for opening a connection with a foreign host over the internet?
• Design and describe a system/application that will most efficiently produce a report of the top 1 million Google search requests. These are the particulars: 1) You are given 12 servers to work with. They are all dual-processor machines with 4Gb of RAM, 4x400GB hard drives and networked together.(Basically, nothing more than high-end PC’s) 2) The log data has already been cleaned for you. It consists of 100 Billion log lines, broken down into 12 320 GB files of 40-byte search terms per line. 3) You can use only custom written applications or available free open-source software.
• There is an array A[N] of N numbers. You have to compose an array Output[N] such that Output[i] will be equal to multiplication of all the elements of A[N] except A[i]. For example Output[0] will be multiplication of A[1] to A[N-1] and Output[1] will be multiplication of A[0] and from A[2] to A[N-1]. Solve it without division operator and in O(n).
• There is a linked list of numbers of length N. N is very large and you don’t know N. You have to write a function that will return k random numbers from the list. Numbers should be completely random. Hint: 1. Use random function rand() (returns a number between 0 and 1) and irand() (return either 0 or 1) 2. It should be done in O(n).
• Find or determine non existence of a number in a sorted list of N numbers where the numbers range over M, M>> N and N large enough to span multiple disks. Algorithm to beat O(log n) bonus points for constant time algorithm.
• You are given a game of Tic Tac Toe. You have to write a function in which you pass the whole game and name of a player. The function will return whether the player has won the game or not. First you to decide which data structure you will use for the game. You need to tell the algorithm first and then need to write the code. Note: Some position may be blank in the game। So your data structure should consider this condition also.
• You are given an array [a1 To an] and we have to construct another array [b1 To bn] where bi = a1*a2*…*an/ai. you are allowed to use only constant space and the time complexity is O(n). No divisions are allowed.
• How do you put a Binary Search Tree in an array in a efficient manner. Hint :: If the node is stored at the ith position and its children are at 2i and 2i+1(I mean level order wise)Its not the most efficient way.
• How do you find out the fifth maximum element in an Binary Search Tree in efficient manner. Note: You should not use use any extra space. i.e sorting Binary Search Tree and storing the results in an array and listing out the fifth element.
• Given a Data Structure having first n integers and next n chars. A = i1 i2 i3 … iN c1 c2 c3 … cN.Write an in-place algorithm to rearrange the elements of the array ass A = i1 c1 i2 c2 … in cn
• Given two sequences of items, find the items whose absolute number increases or decreases the most when comparing one sequence with the other by reading the sequence only once.
• Given That One of the strings is very very long , and the other one could be of various sizes. Windowing will result in O(N+M) solution but could it be better? May be NlogM or even better?
• How many lines can be drawn in a 2D plane such that they are equidistant from 3 non-collinear points?
• Let’s say you have to construct Google maps from scratch and guide a person standing on Gateway of India (Mumbai) to India Gate(Delhi). How do you do the same?
• Given that you have one string of length N and M small strings of length L. How do you efficiently find the occurrence of each small string in the larger one?
• Given a binary tree, programmatically you need to prove it is a binary search tree.
• You are given a small sorted list of numbers, and a very very long sorted list of numbers – so long that it had to be put on a disk in different blocks. How would you find those short list numbers in the bigger one?
• Suppose you have given N companies, and we want to eventually merge them into one big company. How many ways are theres to merge?
• Given a file of 4 billion 32-bit integers, how to find one that appears at least twice?
• Write a program for displaying the ten most frequent words in a file such that your program should be efficient in all complexity measures.
• Design a stack. We want to push, pop, and also, retrieve the minimum element in constant time.
• Given a set of coin denominators, find the minimum number of coins to give a certain amount of change.
• Given an array, i) find the longest continuous increasing subsequence. ii) find the longest increasing subsequence.
• Suppose we have N companies, and we want to eventually merge them into one big company. How many ways are there to merge?
• Write a function to find the middle node of a single link list.
• Given two binary trees, write a compare function to check if they are equal or not. Being equal means that they have the same value and same structure.
• Implement put/get methods of a fixed size cache with LRU replacement algorithm.
• You are given with three sorted arrays ( in ascending order), you are required to find a triplet ( one element from each array) such that distance is minimum.
• Distance is defined like this : If a[i], b[j] and c[k] are three elements then distance=max(abs(a[i]-b[j]),abs(a[i]-c[k]),abs(b[j]-c[k]))” Please give a solution in O(n) time complexity
• How does C++ deal with constructors and deconstructors of a class and its child class?
• Write a function that flips the bits inside a byte (either in C++ or Java). Write an algorithm that take a list of n words, and an integer m, and retrieves the mth most frequent word in that list.
• What’s 2 to the power of 64?
• Given that you have one string of length N and M small strings of length L. How do you efficiently find the occurrence of each small string in the larger one?
• How do you find out the fifth maximum element in an Binary Search Tree in efficient manner.
• Suppose we have N companies, and we want to eventually merge them into one big company. How many ways are there to merge?
• There is linked list of millions of node and you do not know the length of it. Write a function which will return a random number from the list.
• You need to check that your friend, Bob, has your correct phone number, but you cannot ask him directly. You must write a the question on a card which and give it to Eve who will take the card to Bob and return the answer to you. What must you write on the card, besides the question, to ensure Bob can encode the message so that Eve cannot read your phone number?
• How long it would take to sort 1 trillion numbers? Come up with a good estimate.
• Order the functions in order of their asymptotic performance: 1) 2^n 2) n^100 3) n! 4) n^n
• There are some data represented by(x,y,z). Now we want to find the Kth least data. We say (x1, y1, z1) > (x2, y2, z2) when value(x1, y1, z1) > value(x2, y2, z2) where value(x,y,z) = (2^x)*(3^y)*(5^z). Now we can not get it by calculating value(x,y,z) or through other indirect calculations as lg(value(x,y,z)). How to solve it?
• How many degrees are there in the angle between the hour and minute hands of a clock when the time is a quarter past three?
• Given an array whose elements are sorted, return the index of a the first occurrence of a specific integer. Do this in sub-linear time. I.e. do not just go through each element searching for that element.
• Given two linked lists, return the intersection of the two lists: i.e. return a list containing only the elements that occur in both of the input lists.
• What’s the difference between a hashtable and a hashmap?
• If a person dials a sequence of numbers on the telephone, what possible words/strings can be formed from the letters associated with those numbers?
• How would you reverse the image on an n by n matrix where each pixel is represented by a bit?
• Create a fast cached storage mechanism that, given a limitation on the amount of cache memory, will ensure that only the least recently used items are discarded when the cache memory is reached when inserting a new item. It supports 2 functions: String get(T t) and void put(String k, T t).
• Create a cost model that allows Google to make purchasing decisions on to compare the cost of purchasing more RAM memory for their servers vs. buying more disk space.
• Design an algorithm to play a game of Frogger and then code the solution. The object of the game is to direct a frog to avoid cars while crossing a busy road. You may represent a road lane via an array. Generalize the solution for an N-lane road.
• What sort would you use if you had a large data set on disk and a small amount of ram to work with?
• What sort would you use if you required tight max time bounds and wanted highly regular performance.
• How would you store 1 million phone numbers?
• Design a 2D dungeon crawling game. It must allow for various items in the maze – walls, objects, and computer-controlled characters. (The focus was on the class structures, and how to optimize the experience for the user as s/he travels through the dungeon.)
• What is the size of the C structure below on a 32-bit system? On a 64-bit?

struct foo {

char a;

char* b;

};

Google Interview: Software Engineer in Test

• Efficiently implement 3 stacks in a single array.
• Given an array of integers which is circularly sorted, how do you find a given integer.
• Write a program to find depth of binary search tree without using recursion.
• Find the maximum rectangle (in terms of area) under a histogram in linear time.
• Most phones now have full keyboards. Before there there three letters mapped to a number button. Describe how you would go about implementing spelling and word suggestions as people type.
• Describe recursive mergesort and its runtime. Write an iterative version in C++/Java/Python.
• How would you determine if someone has won a game of tic-tac-toe on a board of any size?
• Given an array of numbers, replace each number with the product of all the numbers in the array except the number itself *without* using division.
• Create a cache with fast look up that only stores the N most recently accessed items.
• How to design a search engine? If each document contains a set of keywords, and is associated with a numeric attribute, how to build indices?
• Given two files that has list of words (one per line), write a program to show the intersection.
• What kind of data structure would you use to index annagrams of words? e.g. if there exists the word “top” in the database, the query for “pot” should list that.

Google Interview: Quantitative Compensation Analyst

• What is the yearly standard deviation of a stock given the monthly standard deviation?
• How many resumes does Google receive each year for software engineering?
• Anywhere in the world, where would you open up a new Google office and how would you figure out compensation for all the employees at this new office?
• What is the probability of breaking a stick into 3 pieces and forming a triangle?

Google Interview: Engineering Manager

• You’re the captain of a pirate ship, and your crew gets to vote on how the gold is divided up. If fewer than half of the pirates agree with you, you die. How do you recommend apportioning the gold in such a way that you get a good share of the booty, but still survive?

Google Interview: AdWords Associate

• How would you work with an advertiser who was not seeing the benefits of the AdWords relationship due to poor conversions?
• How would you deal with an angry or frustrated advertisers on the phone?

Sources

http://news.ycombinator.com/item?id=266663

http://tihomir.org/crazy-questions-at-google-job-interview/

http://www.drizzle.com/~jpaint/google.html

http://www.gamedev.net/community/forums/topic.asp?topic_id=299692

http://careers.cse.sc.edu/googleinterview

http://job-interview.blogspot.com/2005/02/google-interview-product-marketing.html

http://www.theregister.co.uk/2007/01/05/google_interview_tales/

http://money.cnn.com/2007/08/29/technology/brain_teasers.biz2/index.htm

http://blogs.lessthandot.com/index.php/ITProfessionals/EthicsIT/google-interview-questions

http://placementsindia.blogspot.com/2007/09/google-top-interview-puzzles.html

http://linkmingle.com/user/interview_questions/google_interview_questions

http://discuss.joelonsoftware.com/default.asp?interview.11.626758.33

http://mindcipher.com/puzzle/78-clock-works

http://www.glassdoor.com

http://bluepixel.ca/blog/?p=69

http://www.businessinsider.com/my-nightmare-interviews-with-google-2009-11