Word Ladder Problem

Problem: Given two words (start and end), and a dictionary, find the length of shortest transformation sequence from start to end, such that: Only one letter can be changed at a time. Each intermediate word must exist in the dictionary For example, Given: start = “hit” end = “cog” dict = ["hot","dot","dog","lot","log"] As one shortest Read More →

How to Check if a given Number is Fibonacci number?

In mathematics, the Fibonacci numbers or Fibonacci sequence are the numbers in the following integer sequence: 1,1,2,3,5,8,13,21,34,55,89,144.. A simple way is to generate Fibonacci numbers until the generated number is greater than or equal to ‘x’. Following is an interesting property about Fibonacci numbers that can also be used to check if a given number Read More →

Product of All Other Array Numbers

Problem: Given an array of n integers where n>1, return an array of same size an input array where at every index of the output array should contain the product of all elements in the array except the element at the given index. Example: arr[] = {10, 4, 1, 6, 2} prod[] = {48,120,480,80,240} Solution: Read More →

Oxigen Wallet Interview Questions – Set 1

Round 1: Online coding test on Cocubes.com Round 2: Q1. Linked list multiplication: Given two linked list that represents polynomial return a pointer to linked list which is multiplication of the two. struct node { int coeff; int exp; struct node*next; }; example: 4x(2)-2x+1 x-1 answer : 4x(3)-6x(2)+3x-1 Q2. Suppose when user chooses OxygenWallet as Read More →

Flipkart Interview Questions – Set 6

I had interview with Flipkart for SDE . There was two technical round both guys was cool and interview process was very nice when i got stuck they provide me hint. Round 1: Q1. You have a infinite stream of repeated number find top K frequent number from this stream and discussion on this question Read More →

Find the Missing Element in Arithmetic Progression

Problem: Find the missing number in an Arithmetic Progression. An Arithmetic Progression is defined as one in which there is a constant difference between the consecutive terms of a given series of numbers. You are provided with consecutive elements of an Arithmetic Progression. There is however one hitch: exactly one number from the original series Read More →

Find a Peak Element in Array

Question: A peak element in an integer array is defined as an element that is greater than its neighbors. Given an input array where num[i] ≠ num[i+1], find a peak element and return its index. The array may contain multiple peaks, in that case return the index to any one of the peaks is fine. Read More →

Check if Binary Tree is Height Balanced?

Given a binary tree, determine if it is height-balanced. A height-balanced binary tree is defined as a binary tree in which the depth of the two subtrees of every node never differ by more than 1. The solution presented is a recursive. Find the height of left and right subtrees and check the difference of Read More →

Paytm Interview Questions – Set 2

Crazyforcode has helped me a lot. In order to help other students I would like to share my experience. Tech Round 1: Q1. How will you balance a binary search tree? Q2. Implement two stack in an array . Interviewer was confused about questions so he doesn’t ask about it? Q3. The other question was Read More →

Macros vs Functions

Macros are pre-processed which means that all the macros would be processed before your program compiles. However, functions are not preprocessed but compiled. See the following example of Macro: Output: 10 See the following example of Function: Output: 10 In short, Macro features: Macro is Preprocessed No Type Checking Code Length Increases Use of macro Read More →

Depth-first search (DFS) – Algorithms and Data Structures


Depth-first search starts a graph’s traversal by visiting an arbitrary vertex and marking it as visited. On each iteration, the algorithm proceeds to an unvisited vertex that is adjacent to the one it is currently in. (If there are several such vertices, a tie can be resolved arbitrarily. As a practical matter, which of the Read More →

Rope Escape Puzzle

Puzzle: Jim is trapped at the top of a building which is 200m high. He has with him a rope 150m long. There is a hook at the top where he stands. Looking down, he notices that midway between him and the ground, at a height of 100m, there is a ledge with another hook. Read More →