700+ Full Stack Developer Interview Questions and Answers

You are given a positive integer ‘N’. The task is to find and return the smallest number, ‘M’, such that the multiplication of all the digits in ‘M’ is equal to...read more

You are given an arbitrary binary tree consisting of N nodes, where each node is associated with a certain value, and two node values, a and b, you need to check if these nodes are...read more

You are given a matrix of ‘M’ rows and ‘N’ columns. The cells of the matrix contain either a coin or are empty.

You are allowed to visit every boundary cell that has a coin in it ...read more

You have been given an undirected graph with 'N' vertices and 'M' edges. The vertices are labelled from 1 to 'N'.

Your task is to find if the graph contains a cycle or not.

A ...read more

You have been given a binary tree of integers. You are supposed to find the left view of the binary tree. The left view of a binary tree is the set of all nodes that are visible when t...read more

Implement a queue data structure which follows FIFO(First In First Out) property, using only the instances of the stack data structure.

Note:

1. To implement means you need to complete some pre...read more

You have been given a long type array/list 'ARR' of size 'N'. It represents an elevation map wherein 'ARR[i]' denotes the elevation of the 'ith' bar. Print the total amount of rainwater that ...read more

You are Harshad Mehta’s friend. He told you the price of a particular stock for the next ‘N’ days. You can either buy or sell a stock. Also, you can only complete at most 2-transactions. Find ...read more

You have a robot currently standing at the origin (0, 0) of a two-dimensional grid and facing north direction. You are given a sequence of moves for the robot in the form of a string of size 'N'. Y...read more

You are given an array ‘Arr’ consisting of ‘N’ distinct integers and a positive integer ‘K’. Find out Kth smallest and Kth largest element of the array. It is guaranteed...read more

You have been given a grid containing some oranges. Each cell of this grid has one of the three integers values:

Value 0 - representing an empty cell.

Value 1 - representing a fresh orange.

...read more

A Directed Acyclic Graph (DAG) is a directed graph that contains no cycles.

Topological Sorting of DAG is a linear ordering of vertices such that for every directed edge from vertex ‘u’ to verte...read more

Given a binary tree. Find and return the modulus of the difference between the sum of odd level nodes and the sum of even level nodes.

Input format:

The first line contains an integer 'T' which de...read more

Alex has a computer with ‘K’ memory spaces. He has a list of ‘N’ different document downloads that he would like to do, each of which consumes some unique memory usage. He also has ‘M’ comp...read more

There are 100 doors in a row, all doors are initially closed. A person walks through all doors multiple times and toggle (if open then close, if close then open) them in the following way:

In the first wa...read more

Given a sequence of numbers ‘ARR’. Your task is to return a sorted sequence of ‘ARR’ in non-descending order with help of the merge sort algorithm.

Example :

Merge Sort Algorithm - Merge sort is a Div...read more

You are given an integer array 'ARR' of size 'N' and an integer 'S'. Your task is to return the list of all pairs of elements such that each sum of elements of each pair equals 'S'.

Note:

Each pair shou...read more

You are given two strings named str1 and str2 of length N and M respectively. Find whether string str2 contains one of the permutations of string str1 as its substring. In other words, whet...read more

You are given two strings BEGIN and END and an array of strings DICT. Your task is to find the length of the shortest transformation sequence from BEGIN to END such that in every transformation you c...read more

You have been given an array/list of strings 'STR_LIST'. You are supposed to return the strings as groups of anagrams such that strings belonging to a particular group are anagrams of one...read more

You are given an array/list ARR consisting of N integers. Your task is to find the maximum possible sum of a non-empty subarray(contagious) of this array.

Note: An array C is a subarray of a...read more

You have been given an array 'ARR' of 'N' distinct elements.

Your task is to find the minimum no. of swaps required to sort the array.

For example:

For the given...read more

You are given a positive integer ‘N’ denoting the number of tasks you need to finish. You can directly start performing any task, but some tasks have some prerequisites, i.e. to perform some ta...read more

You have been given a binary tree of integers with N number of nodes. Your task is to check if that input tree is a BST (Binary Search Tree) or not.

A binary search tree (BST) is a binary tree data ...read more

Write a program to count and print the total number of characters (lowercase english alphabets only), digits (0 to 9) and white spaces (single space, tab i.e. '\t' and newline i.e. '\n') entered...read more

Bob lives with his wife in a city named Berland. Bob is a good husband, so he goes out with his wife every Friday to ‘Arcade’ mall.

‘Arcade’ is a very famous mall in Berland. It has a very unique t...read more

You have been given a non-empty grid consisting of only 0s and 1s. You have to find the number of islands in the given grid.

An island is a group of 1s (representing land) connected horizontall...read more

You have been given an integer array/list(arr) and a number 'Sum'. Find and return the total number of pairs in the array/list which when added, results equal to the 'Sum'.

Note:

G...read more

You are given an arbitrary binary tree, a node of the tree, and an integer 'K'. You need to find all such nodes which have a distance K from the given node and return ...read more

You have been given a non-empty grid ‘MAT’ with 'N' rows and 'M' columns consisting of only 0s and 1s. All the rows are sorted in ascending order.

Your task is to find the index of the row t...read more

You have been given a binary matrix of size 'N' * 'M' where each element is either 0 or 1. You are also given a source and a destination cell, both of them lie within the matrix....read more

You have been given two integers 'N' and 'D', Your task is to find the square root of the number 'N' with precision up to 'D' decimal places i.e. the difference between your answer and the ...read more

Given a string ’S’ consisting of lower case English letters, you are supposed to return the longest palindromic substring of ‘S’.

Note that in case of more than one longest palindro...read more

You are given an N * N matrix of integers where each row and each column is sorted in increasing order. You are given a target integer 'X'. Find the position of...read more

You are given an array 'ARR' consisting of 'N' elements, and you need to find the maximum value of sum(i * ARR[i]) among all possible rotation...read more

You are given an array of strings 'ARRSTR[]' of size 'N' and a character 'C'. Your task is to sort the 'ARRSTR[]' according to the new alphabetical order that starts with the given characte...read more

Given a binary tree with N number of nodes, check if that input tree is BST (Binary Search Tree) or not. If yes, return true, return false otherwise.

A binary search tree (BST) is a binary tree data...read more

In how many ways can we position an HTML element? Or what are the permissible values of the position attribute?

You are given an array 'ARR' of integers of length N. Your task is to find the first missing positive integer in linear time and constant space. In other words, find the lowest positive in...read more

You are given two integers ‘dividend’ and ‘divisor’. You are required is to divide the integers without using multiplication, division and modular operators. Your task is to return the quotie...read more

Given a string, determine if it is a palindrome, considering only alphanumeric characters.

Palindrome

A palindrome is a word, number, phrase, or other sequences of characters which read the sam...read more

You are given an array 'ARR' of N integers. Each integer represents the height of a balloon. So, there are N balloons lined up.

Your aim is to destroy all these balloons. Now, a balloon can onl...read more

Given an array ‘pre[]’ of ‘n’ elements that represent Preorder traversal of a spacial binary tree where every node has either 0 or 2 children. Also Given a boolean array ‘i...read more

Given a sequence of ‘N’ space-separated non-negative integers A[1],A[2],A[3],......A[i]…...A[n]. Where each number of the sequence represents the height of the line drawn at point 'i'. ...read more

You are given 'N' rectangular buildings in a 2-dimensional city. Your task is to compute the skyline of these buildings, eliminating hidden lines return the skyline formed by these buildings ...read more

You have been given a board where there are '2' rows and 'N' columns. You have an infinite supply of 2x1 tiles, and you can place a tile in the following ways:

1. Horizontally as 1x2 tile 2. Verti...read more

Mr. X is a professional robber planning to rob houses along a street. Each house has a certain amount of money hidden. All houses along this street are arranged in a circle. That means the first hou...read more