Brainteaser Interview Questions


Top 5 BRAINTEASER Interview Questions (With Answers)



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Who Am I Riddles For Kids  

10 ‘Who Am I’ IQs and Riddles With Answers For Kids and All  

Common Riddles

1) What has a face and two hands but no arms or legs?

2) What is the easiest way to double your money?

3) What has a thumb and four fingers but is not alive?

4) What has to be broken before you can use it?

5) What has a neck but no head?

6) What gets wetter as it dries?

7) What goes up and doesn’t come back down?

8) What belongs to you but is used more by others?

9) Everyone has it and no one can lose it, what is it?

10) It’s been around for millions of years, but it’s no more than a month old. What is it?


Below is a list of brainteasers that Microsoft has asked at interviews:


  1. A band is going in the street with a constant speed. Someone in the last row has a dog. The dog runs ahead, reaches the front row of the band and gets back to it’s owner. The dog’s speed was constant all the way and while it was running the band passed 50 feet. Find the length of the dog’s path, if the distance between the front and the rear row of the band is 50 feet.
  2. Design a coffee maker that will be used by astronauts.
  3. Design a communication device for Canadian park rangers.
  4. Design a GPS navigation unit for a hiker.
  5. Design a music system for a car. What are the features? Draw a picture.
  6. Design a remote control for an automatic window-blind system.
  7. Design a search function.
  8. Design an alarm clock for a blind person.
  9. Design an alarm clock.
  10. Design an instant messaging system.
  11. Develop an algorithm for selecting objects in Visio.
  12. Did you have a moment of epiphany when you KNEW what you wanted to be when you grew up?
  13. Explain a database to a young child.
  14. Explain the Internet to your grandparents
  15. Give a good method to count the number of ones in a “n” (e.g. 32) bit number.
  16. Give a one-line C expression to test whether a number is a power of 2. No loops allowed.
  17. Given a MAKEFILE, design the data structure that a parser would create and then write code that iterates over that data structure executing commands if needed.
  18. Given a rectangular (cuboid 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?
  19. 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.
  20. 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 ].
  21. Given only putchar (no sprintf, itoa, etc.) write a routine putlong that prints out an unsigned long in decimal.
  22. How does Microsoft fit into your vision?
  23. How many cars are there in the USA?
  24. How many times a day do the hands on a clock overlap themselves?
  25. How would go about finding out where to find a book in a library. (You do not know how exactly the books are organized beforehand).
  26. How would you deal with a bug that no one wants to fix? Both the SDE and his lead have said they won’t fix it.
  27. How would you deal with changes being made a week or so before the ship date?
  28. How would you explain what a database is to a 5-year-old?
  29. How would you test a keyboard?
  30. How would you test a pen?
  31. How would you test a program that takes in two points and outputs the distance between the two points?
  32. How would you test a vending machine?
  33. How would you test an elevator?
  34. I am your grandmother. Describe what MATLAB is to me.
  35. 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.
  36. If you could remove any of the 50 states, which state would it be and why?
  37. If you had an infinite supply of water and a 5 quart and 3 quart pail, how would you measure exactly 4 quarts?
  38. 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?
  39. 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?
  40. Insert in a sorted list.
  41. 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?
  42. Reverse a linked list.
  43. Steve Jobs calls and asks you to improve the iPod. Go.
  44. Suppose you are one week away from the product shipping date and discover a bug in your software. What do you do?
  45. Tell me about a time when you made a decision and later found out that it was incorrect. What did you do to resolve the issue?
  46. Test the save dialog in Notepad.
  47. Test the Windows scroll bar.
  48. The government wants cars to keep track of whether or not they are speeding. The part to determine this is already able to determine the speed of the vehicle, how would you design the rest of the system.
  49. There are 3 baskets. One of them has 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.
  50. There are four ants 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?
  51. What are examples of poorly designed software?
  52. What are some examples of poorly/well-designed software? What makes the software this way and how would you change it?
  53. What are some self-directed missions that may have influenced your career direction?
  54. What are some things that excite and motivate you?
  55. What are the different ways to implement a condition where the value of x can be either a 0 or a 1?
  56. What is your favorite Microsoft product? Why?
  57. What is your favorite web site? Why? Now improve it.
  58. What is your least favorite Microsoft product? Why?
  59. What types of projects (academic or otherwise) have inspired you in the past?
  60. What’s an example of great product design?
  61. Which way should the key turn in a car door to unlock it?
  62. Why do mirrors reverse right and left instead of up and down?
  63. Why do you want to work for Microsoft?
  64. Why is a manhole cover round?
  65. Write a function that counts the number of primes in the range [1-N]. Write the test cases for this function.
  66. Write a function that inserts an integer into a linked list in ascending order. Write the test cases for this function.
  67. Write a function that will return the number of days in a month (no using System.DateTime).
  68. Write a routine to draw a circle (x ** 2 + y ** 2 = r ** 2) without making use of any floating point computations at all.
  69. Write the InStr function. Write the test cases for this function.
  70. Write the test cases for a vending machine.
  71. You have 3 jars. Each jar has a label on it: white, black, or white & black. You have 3 sets of marbles: white, black, and white & black. One set is stored in one jar. The labels on the jars are guaranteed to be incorrect (i.e. white will not contain white). Which jar would you choose from to give you the best chances of identifying which set of marbles in is in which jar.
  72. 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?
  73. 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?
  74. 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?
  75. 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?
  76. 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.
  77. 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?

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