Browsing the blog archives for January, 2010

How Strong is an Egg?

Question: You have two identical eggs. Standing in front of a 100 floor building, you wonder what is the maximum number of floors from which the egg can be dropped without breaking it. What is the minimum number of tries needed to find out the solution? Answer: The easiest way to do this would be […]

81 Comments

Reverse a Linked-List

Question: Reverse a Linked-list. Write code in C. Answer: There are multiple ways to go about this. Let’s first look at a recursive solution. Node * reverse( Node * ptr , Node * previous) { Node * temp; if(ptr->next == NULL) { ptr->next = previous; return ptr; } else { temp = reverse(ptr->next, ptr); ptr->next […]

Is Your Husband a Cheat?

Question: A┬ácertain town comprises of 100 married couples. Everyone in the town lives by the following rule: If a husband cheats on his wife, the husband is executed as soon as his wife finds out about him. All the women in the town only gossip about the husbands of other women. No woman ever tells […]

27 Comments

Boys and Girls

Question: In a country where everyone wants a boy, each family continues having babies till they have a boy. After some time, what is the proportion of boys to girls in the country? (Assuming probability of having a boy or a girl is the same) Answer: This is a very simple probability question in a […]

Probability of a Car Passing By

Question: The probability of a car passing a certain intersection in a 20 minute windows is 0.9. What is the probability of a car passing┬áthe intersection in a 5 minute window? (Assuming a constant probability throughout) Answer: This is one of the basic probability question asked in a software interview. Let’s start by creating an […]

13 Comments

Sub-Array with the Largest Sum

Question: You are given an array with integers (both positive and negative) in any random order. Find the sub-array with the largest sum. Answer: This is an all-time favorite software interview question. The best way to solve this puzzle is to use Kadane’s algorithm which runs in O(n) time. The idea is to keep scanning […]

How Old Are My Children?

Question: Two old friends, Jack and Bill, meet after a long time. Jack: Hey, how are you man? Bill: Not bad, got married and I have three kids now. Jack: That’s awesome. How old are they? Bill: The product of their ages is 72 and the sum of their ages is the same as your […]

22 Comments

5 Pirates Fight for 100 Gold Coins

Question: Five pirates discover a chest containing 100 gold coins. They decide to sit down and devise a distribution strategy. The pirates are ranked based on their experience (Pirate 1 to Pirate 5, where Pirate 5 is the most experienced). The most experienced pirate gets to propose a plan and then all the pirates vote […]

Four People on a Rickety Bridge

Question: Four people need to cross a rickety bridge at night. Unfortunately, they have only one torch and the bridge is too dangerous to cross without one. The bridge is only strong enough to support two people at a time. Not all people take the same time to cross the bridge. Times for each person: […]

26 Comments

Apples and Oranges?

Question: You have 3 baskets, one with apples, one with oranges and one with both apples and oranges mixed. Each basket is closed and is labeled with ‘Apples’, ‘Oranges’ and ‘Apples and Oranges’. However, each of these labels is always placed incorrectly. How would you pick only one fruit from a basket to place the […]

0 Comments