Infosys Coding Interview Questions

Two Sum

Given an array of integers nums and an integer target, return the indices of the two numbers that add up to target.

Find Building Where Alice and Bob Can Meet

You are given a 0-indexed array heights of positive integers, where heights[i] represents the height of the ith building.

Minimum Reverse Operations

You are given an integer n and an integer p representing an array arr of length n where all elements are set to 0's, except position p which is set to 1. You ar...

Count the Number of Ideal Arrays

You are given two integers n and maxValue, which are used to describe an ideal array.

Transform Array By Parity

You are given an integer array nums. Transform nums by performing the following operations in the exact order specified: Replace each even number with 0, replac...

Longest Substring Without Repeating Characters

Given a string s, find the length of the longest substring without duplicate characters.

Eat Pizzas

You are given an integer array pizzas of size n, where pizzas[i] represents the weight of the ith pizza. Every day, you eat exactly 4 pizzas. When you eat pizza...

Maximum Sum of Subsequence With Non-adjacent Elements

You are given an array nums consisting of integers. You are also given a 2D array queries, where queries[i] = [posi, xi].

Stone Game VIII

Alice and Bob take turns playing a game, with Alice starting first.

Best Time to Buy and Sell Stock

You are given an array prices where prices[i] is the price of a given stock on the ith day.

The Number of Beautiful Subsets

You are given an array nums of positive integers and a positive integer k.

Can Convert String in K Moves

Given two strings s and t, your goal is to convert s into t in k moves or less.

Number of Beautiful Integers in the Range

You are given positive integers low, high, and k.

Sort the People

You are given an array of strings names, and an array heights that consists of distinct positive integers. Both arrays are of length n.

Determine the Minimum Sum of a k-avoiding Array

You are given two integers, n and k.

Maximize The Minimum Game Score

You are given an array points of size n and an integer m. There is another array gameScore of size n, where gameScore[i] represents the score achieved at the it...

Find the Minimum Possible Sum of a Beautiful Array

You are given positive integers n and target.

Maximum Number of Consecutive Values You Can Make

You are given an integer array coins of length n which represents the n coins that you own. The value of the ith coin is coins[i]. You can make some value x if...

Minimum Addition to Make Integer Beautiful

You are given two positive integers n and target.

Minimum Total Distance Traveled

There are some robots and factories on the X-axis. You are given an integer array robot where robot[i] is the position of the ith robot. You are also given a 2D...

Maximum Segment Sum After Removals

You are given two 0-indexed integer arrays nums and removeQueries, both of length n. For the ith query, the element in nums at the index removeQueries[i] is rem...

Find The Number Of Subsequences With Equal Gcd

You are given an integer array nums. Your task is to find the number of pairs of non-empty subsequences (seq1, seq2) of nums that satisfy two conditions: the su...

Maximum Product After K Increments

You are given an array of non-negative integers nums and an integer k. In one operation, you may choose any element from nums and increment it by 1.

Valid Parentheses

Given a string s containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.

Largest Number After Mutating Substring

You are given a string num, which represents a large integer. You are also given a 0-indexed integer array change of length 10 that maps each digit 0-9 to anoth...

Longest Well-Performing Interval

We are given hours, a list of the number of hours worked per day for a given employee.

Next Permutation

A permutation of an array of integers is an arrangement of its members into a sequence or linear order.

Merge Sorted Array

You are given two integer arrays nums1 and nums2, sorted in non-decreasing order, and two integers m and n, representing the number of elements in nums1 and num...

Maximum Subarray

Given an integer array nums, find the subarray with the largest sum, and return its sum.

Palindrome Number

Given an integer x, return true if x is a palindrome, and false otherwise.

Remove Duplicates from Sorted Array

Given an integer array nums sorted in non-decreasing order, remove the duplicates in-place such that each unique element appears only once. The relative order o...

Reverse String

Write a function that reverses a string. The input string is given as an array of characters s.

Rotate Image

You are given an n x n 2D matrix representing an image, rotate the image by 90 degrees (clockwise).

Longest Common Prefix

Write a function to find the longest common prefix string amongst an array of strings.

Valid Anagram

Given two strings s and t, return true if t is an anagram of s, and false otherwise.

Product of Array Except Self

Given an integer array nums, return an array answer such that answer[i] is equal to the product of all the elements of nums except nums[i].

Second Highest Salary

Table: Employee

Trapping Rain Water

Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it can trap after raining.

Generate Parentheses

Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses.

Coin Change

You are given an integer array coins representing coins of different denominations and an integer amount representing a total amount of money.

Spiral Matrix

Given an m x n matrix, return all elements of the matrix in spiral order.

Merge Intervals

Given an array of intervals where intervals[i] = [starti, endi], merge all overlapping intervals, and return an array of the non-overlapping intervals that cove...

3Sum

Given an integer array nums, return all the triplets [nums[i], nums[j], nums[k]] such that i != j, i != k, and j != k, and nums[i] + nums[j] + nums[k] == 0.

Rotate Array

Given an integer array nums, rotate the array to the right by k steps, where k is non-negative.

Group Anagrams

Given an array of strings strs, group the anagrams together. You can return the answer in any order.

Reverse Integer

Given a signed 32-bit integer x, return x with its digits reversed. If reversing x causes the value to go outside the signed 32-bit integer range [-231, 231 - 1...

Fibonacci Number

The Fibonacci numbers, commonly denoted F(n) form a sequence, called the Fibonacci sequence, such that each number is the sum of the two preceding ones, startin...

Palindrome Partitioning

Given a string s, partition s such that every substring of the partition is a palindrome. Return all possible palindrome partitioning of s.

Merge Two Sorted Lists

You are given the heads of two sorted linked lists list1 and list2.

Reverse Nodes in k-Group

Given the head of a linked list, reverse the nodes of the list k at a time, and return the modified list.

Move Zeroes

Given an integer array nums, move all 0's to the end of it while maintaining the relative order of the non-zero elements.

Number of Islands

Given an m x n 2D binary grid grid which represents a map of '1's (land) and '0's (water), return the number of islands.

Longest Consecutive Sequence

Given an unsorted array of integers nums, return the length of the longest consecutive elements sequence.

Single Element in a Sorted Array

You are given a sorted array consisting of only integers where every element appears exactly twice, except for one element which appears exactly once.

Gas Station

There are n gas stations along a circular route, where the amount of gas at the ith station is gas[i].

Two Sum II - Input Array Is Sorted

Given a 1-indexed array of integers numbers that is already sorted in non-decreasing order, find two numbers such that they add up to a specific target number....

Sort an Array

Given an array of integers nums, sort the array in ascending order and return it.

Find the Index of the First Occurrence in a String

Given two strings needle and haystack, return the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.

House Robber

You are a professional robber planning to rob houses along a street. Each house has a certain amount of money stashed, the only constraint stopping you from rob...

Add Two Numbers

You are given two non-empty linked lists representing two non-negative integers. The digits are stored in reverse order, and each of their nodes contains a sing...

Reverse Words in a String

Given an input string s, reverse the order of the words.

Longest Palindromic Substring

Given a string s, return the longest palindromic substring in s.

Missing Number

Given an array nums containing n distinct numbers in the range [0, n], return the only number in the range that is missing from the array.

Kth Largest Element in an Array

Given an integer array nums and an integer k, return the kth largest element in the array.

Climbing Stairs

You are climbing a staircase. It takes n steps to reach the top.

Rearrange Array Elements by Sign

You are given a 0-indexed integer array nums of even length consisting of an equal number of positive and negative integers.

Sqrt(x)

Given a non-negative integer x, return the square root of x rounded down to the nearest integer. The returned integer should be non-negative as well.

Roman to Integer

Roman numerals are represented by seven different symbols: I, V, X, L, C, D and M.

Median of Two Sorted Arrays

Given two sorted arrays nums1 and nums2 of size m and n respectively, return the median of the two sorted arrays.

Maximum Depth of Binary Tree

Given the root of a binary tree, return its maximum depth.

Edit Distance

Given two strings word1 and word2, return the minimum number of operations required to convert word1 to word2.

Valid Palindrome

A phrase is a palindrome if, after converting all uppercase letters into lowercase letters and removing all non-alphanumeric characters, it reads the same forwa...

Koko Eating Bananas

Koko loves to eat bananas. There are n piles of bananas, the ith pile has piles[i] bananas. The guards have gone and will come back in h hours.

Combination Sum II

Given a collection of candidate numbers (candidates) and a target number (target), find all unique combinations in candidates where the candidate numbers sum to...

Pow(x, n)

Implement pow(x, n), which calculates x raised to the power n (i.e., xn).

Subsets

Given an integer array nums of unique elements, return all possible subsets (the power set).

Container With Most Water

You are given an integer array height of length n. There are n vertical lines drawn such that the two endpoints of the ith line are (i, 0) and (i, height[i]).

Maximum Score Words Formed by Letters

Given a list of words, list of single letters (might be repeating) and score of every character.

Create a DataFrame from List

Write a solution to create a DataFrame from a 2D list called studentdata. This 2D list contains the IDs and ages of some students.

Implement Queue using Stacks

Implement a first in first out (FIFO) queue using only two stacks. The implemented queue should support all the functions of a normal queue (push, peek, pop, an...

Jump Game

You are given an integer array nums. You are initially positioned at the array's first index, and each element in the array represents your maximum jump length...

String to Integer (atoi)

Implement the myAtoi(string s) function, which converts a string to a 32-bit signed integer.

Search in Rotated Sorted Array

There is an integer array nums sorted in ascending order (with distinct values).

Minimum Window Substring

Given two strings s and t of lengths m and n respectively, return the minimum window substring of s such that every character in t (including duplicates) is inc...

4Sum

Given an array nums of n integers, return an array of all the unique quadruplets [nums[a], nums[b], nums[c], nums[d]] such that:

Best Time to Buy and Sell Stock II

You are given an integer array prices where prices[i] is the price of a given stock on the ith day.

Combination Sum

Given an array of distinct integers candidates and a target integer target, return a list of all unique combinations of candidates where the chosen numbers sum...

To Lower Case

Given a string s, return the string after replacing every uppercase letter with the same lowercase letter.

Average Time of Process per Machine

Table: Activity

Find the Duplicate Number

Given an array of integers nums containing n + 1 integers where each integer is in the range [1, n] inclusive.

Binary Search

Given an array of integers nums which is sorted in ascending order, and an integer target, write a function to search target in nums. If target exists, then ret...

Subarray Sum Equals K

Given an array of integers nums and an integer k, return the total number of subarrays whose sum equals to k.

Kids With the Greatest Number of Candies

There are n kids with candies. You are given an integer array candies, where each candies[i] represents the number of candies the ith kid has, and an integer ex...

Car Fleet

There are n cars at given miles away from the starting mile 0, traveling to reach the mile target.

Isomorphic Strings

Given two strings s and t, determine if they are isomorphic.

Greatest Common Divisor of Strings

For two strings s and t, we say "t divides s" if and only if s = t + t + t + ... + t + t (i.e., t is concatenated with itself one or more times).

Integer to Roman

Seven different symbols represent Roman numerals with the following values:

Replace Employee ID With The Unique Identifier

Table: Employees

Maximum Product of Three Numbers

Given an integer array nums, find three numbers whose product is maximum and return the maximum product.