100+ Full Stack Developer Interview Questions and Answers for Freshers

Q1. Query and Matrix Problem Statement

You are given a binary matrix with 'M' rows and 'N' columns, initially consisting of all 0s. You will receive 'Q' queries, which can be of four types:

Query 1: 1 R index
Query ...read more

Q2. Most Frequent Non-Banned Word Problem Statement

Given a paragraph consisting of letters in both lowercase and uppercase, spaces, and punctuation, along with a list of banned words, your task is to find the most...read more

Q3. Count Substrings with K Distinct Characters

Given a lowercase string 'STR' and an integer K, the task is to count all possible substrings that consist of exactly K distinct characters. These substrings are not ...read more

Q4. LCA of Binary Tree Problem Statement

You are given a binary tree consisting of distinct integers and two nodes, X and Y. Your task is to find and return the Lowest Common Ancestor (LCA) of these two nodes.

The ...read more

Q6. Reach the Destination Problem Statement

You are given a source point (sx, sy) and a destination point (dx, dy). Determine if it is possible to reach the destination point using only the following valid moves:

...read more

Q8. Find a Node in Linked List

Given a singly linked list of integers, your task is to implement a function that returns the index/position of an integer value 'N' if it exists in the linked list. Return -1 if the ...read more

Q9. Maximum Distance Problem Statement

Given an integer array 'A' of size N, your task is to find the maximum value of j - i, with the restriction that A[i] <= A[j], where 'i' and 'j' are indices of the array.

Inpu...read more

Q10. Add Two Numbers as Linked Lists

You are given two singly linked lists, where each list represents a positive number without any leading zeros.

Your task is to add these two numbers and return the sum as a linke...read more

Q11. Count Inversions Problem Statement

Given an integer array ARR of size N, your task is to find the total number of inversions that exist in the array.

An inversion is defined for a pair of integers in the array ...read more

Q12. Factorial of a Number Problem Statement

You are provided with an integer 'N'. Your task is to calculate and print the factorial of 'N'. The factorial of a number 'N', denoted as N!, is the product of all positi...read more

Q14. LRU Cache Design Question

Design a data structure for a Least Recently Used (LRU) cache that supports the following operations:

1. get(key) - Return the value of the key if it exists in the cache; otherwise, re...read more

Q15. Anagram Pairs Verification Problem

Your task is to determine if two given strings are anagrams of each other. Two strings are considered anagrams if you can rearrange the letters of one string to form the other...read more

Q16. Maximum Consecutive Ones Problem Statement

Given a binary array 'ARR' of size 'N', your task is to determine the maximum length of a sequence consisting solely of 1’s that can be obtained by converting at most ...read more

Array Sum Calculation

Calculate the sum of all elements in an array of length N.

Input:

Line 1: An integer N indicating the size of the array.
Line 2: N integers, the elements of the array, separated by spaces.

Q18. Rotational Equivalence of Strings Problem Statement

Given two strings 'P' and 'Q' of equal length, determine if string 'P' can be transformed into string 'Q' by cyclically rotating it to the right any number of...read more

Q19. Smallest Number with Given Digit Product

Given a positive integer 'N', find and return the smallest number 'M', such that the product of all the digits in 'M' is equal to 'N'. If such an 'M' is not possible or ...read more

Q20. Collect Maximum Coins from Matrix

You are provided with a matrix consisting of 'M' rows and 'N' columns. Each cell in this matrix either contains a coin or is empty.

Your task is to collect the maximum number o...read more

Q21. Cycle Detection in Undirected Graph Problem Statement

You are provided with an undirected graph containing 'N' vertices and 'M' edges. The vertices are numbered from 1 to 'N'. Your objective is to determine whe...read more

Q22. Determine the Left View of a Binary Tree

You are given a binary tree of integers. Your task is to determine the left view of the binary tree. The left view consists of nodes that are visible when the tree is vi...read more

Q23. Queue Using Stacks Implementation

Design a queue data structure following the FIFO (First In First Out) principle using only stack instances.

Explanation:

Your task is to complete predefined functions to suppor...read more

Q24. Buy and Sell Stock Problem Statement

Imagine you are Harshad Mehta's friend, and you have been given the stock prices of a particular company for the next 'N' days. You can perform up to two buy-and-sell transa...read more

Q25. Topological Sort Problem Statement

Given a Directed Acyclic Graph (DAG) consisting of V vertices and E edges, your task is to find any topological sorting of this DAG. You need to return an array of size V repr...read more

Q26. Next Greater Element Problem Statement

Given a list of integers of size N, your task is to determine the Next Greater Element (NGE) for every element. The Next Greater Element for an element X is the first elem...read more

Q27. Optimize Memory Usage Problem Statement

Alex wants to maximize the use of 'K' memory spaces on his computer. He has 'N' different document downloads, each with unique memory usage, and 'M' computer games, each ...read more

Q28. Merge Sort Problem Statement

You are given a sequence of numbers, ARR. Your task is to return a sorted sequence of ARR in non-descending order using the Merge Sort algorithm.

Explanation:

The Merge Sort algorit...read more

Q29. Pair Sum Problem Statement

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

Note:

Each pa...read more

Q30. Permutation In String Problem Statement

Given two strings, str1 and str2, determine whether str2 contains any permutation of str1 as a substring.

Input:

str1 = “ab”
str2 = “aoba”

Output:

True

Example:

Explanatio...read more

Q31. Word Ladder Problem Statement

Given two strings, BEGIN and END, along with an array of strings DICT, determine the length of the shortest transformation sequence from BEGIN to END. Each transformation involves ...read more

Q32. Maximum Subarray Sum Problem Statement

Given an array ARR consisting of N integers, your goal is to determine the maximum possible sum of a non-empty contiguous subarray within this array.

Example of Subarrays:...read more

Q33. Minimum Number of Swaps to Sort an Array

Find the minimum number of swaps required to sort a given array of distinct elements in ascending order.

Input:

T (number of test cases)
For each test case:
N (size of the...read more

Q34. Validate Binary Search Tree (BST)

You are given a binary tree with 'N' integer nodes. Your task is to determine whether this binary tree is a Binary Search Tree (BST).

BST Definition:

A Binary Search Tree (BST)...read more

Q35. Character Counting Challenge

Create a program that counts and prints the total number of specific character types from user input. Specifically, you need to count lowercase English alphabets, numeric digits (0-...read more

Q36. Count Pairs with Given Sum

Given an integer array/list arr and an integer 'Sum', determine the total number of unique pairs in the array whose elements sum up to the given 'Sum'.

Input:

The first line contains ...read more

Q37. Find the Row with the Maximum Number of 1's

You are given a non-empty grid MAT with 'N' rows and 'M' columns, where each element is either 0 or 1. All rows are sorted in ascending order.

Your task is to determi...read more

Q38. Minimum Jumps Problem Statement

Bob and his wife are in the famous 'Arcade' mall in the city of Berland. This mall has a unique way of moving between shops using trampolines. Each shop is laid out in a straight...read more

Q39. Shortest Path in a Binary Matrix Problem Statement

Given a binary matrix of size N * M where each element is either 0 or 1, find the shortest path from a source cell to a destination cell, consisting only of 1s...read more

Q40. Maximum Sum of Products for Array Rotations

You are given an array ARR consisting of N elements. Your task is to determine the maximum value of the summation of i * ARR[i] among all possible rotations of ARR. R...read more

Q41. String Palindrome Verification

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

Input:

The input is a single string without any leading or trailing space...read more

Q42. Circular Move Problem Statement

You have a robot currently positioned at the origin (0, 0) on a two-dimensional grid, facing the north direction. You are given a sequence of moves in the form of a string of len...read more

Q43. The Skyline Problem

Compute the skyline of given rectangular buildings in a 2D city, eliminating hidden lines and forming the outer contour of the silhouette when viewed from a distance. Each building is descri...read more

Q44. Tiling Problem Statement

Given a board with 2 rows and N columns, and an infinite supply of 2x1 tiles, determine the number of distinct ways to completely cover the board using these tiles.

You can place each t...read more

Q45. Middle of a Linked List

You are given the head node of a singly linked list. Your task is to return a pointer pointing to the middle of the linked list.

If there is an odd number of elements, return the middle ...read more

Q46. Build Max Heap Problem Statement

Given an integer array with N elements, the task is to transform this array into a max binary heap structure.

Explanation:

A max-heap is a complete binary tree where each intern...read more

Q47. Delete Node in Binary Search Tree Problem Statement

You are provided with a Binary Search Tree (BST) containing 'N' nodes with integer data. Your task is to remove a given node from this BST.

A BST is a binary ...read more

Q48. Minimum Time Problem Statement

In a city with ‘N’ junctions and ‘M’ bi-directional roads, each junction is connected to other junctions with specified travel times. No road connects a junction to itself, and on...read more

Q49. Alien Dictionary Problem Statement

You are provided with a sorted dictionary (by lexical order) in an alien language. Your task is to determine the character order of the alien language from this dictionary. Th...read more

Q50. Longest Duplicate Substring Problem Statement

You are provided with a string 'S'. The task is to determine the length of the longest duplicate substring within this string. Note that duplicate substrings can ov...read more