Accenture Coding Interview Questions

Bulb Switcher

There are n bulbs that are initially off. You first turn on all the bulbs, then you turn off every second bulb.

Happy Number

Write an algorithm to determine if a number n is happy.

Two Sum

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

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.

Climbing Stairs

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

Palindrome Number

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

Rotate Array

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

Maximum Subarray

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

Roman to Integer

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

Delete and Earn

You are given an integer array nums. You want to maximize the number of points you get by performing the following operation any number of times:

Minimum Right Shifts to Sort the Array

You are given a 0-indexed array nums of length n containing distinct positive integers. Return the minimum number of right shifts required to sort nums and -1 i...

Find Subsequence of Length K With the Largest Sum

You are given an integer array nums and an integer k. You want to find a subsequence of nums of length k that has the largest sum.

Maximum Area of Longest Diagonal Rectangle

You are given a 2D 0-indexed integer array dimensions.

Ant on the Boundary

An ant is on a boundary. It sometimes goes left and sometimes right.

Count Tested Devices After Test Operations

You are given a 0-indexed integer array batteryPercentages having length n, denoting the battery percentages of n 0-indexed devices.

Permutation Difference between Two Strings

You are given two strings s and t such that every character occurs at most once in s and t is a permutation of s.

Sum of Values at Indices With K Set Bits

You are given a 0-indexed integer array nums and an integer k.

Largest Number

Given a list of non-negative integers nums, arrange them such that they form the largest number and return it.

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...

Longest Common Prefix

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

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...

Longest Palindromic Substring

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

Spiral Matrix

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

Shortest Palindrome

You are given a string s. You can convert s to a palindrome by adding characters in front of it.

Majority Element

Given an array nums of size n, return the majority element.

Sort Integers by The Number of 1 Bits

You are given an integer array arr. Sort the integers in the array in ascending order by the number of 1's in their binary representation and in case of two or...

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.

Perfect Squares

Given an integer n, return the least number of perfect square numbers that sum to n.

Longest Substring Without Repeating Characters

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

Find Peak Element

A peak element is an element that is strictly greater than its neighbors.

Reverse Words in a String

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

Valid Anagram

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

Integer Break

Given an integer n, break it into the sum of k positive integers, where k >= 2, and maximize the product of those integers.

Valid Parentheses

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

Plus One

You are given a large integer represented as an integer array digits, where each digits[i] is the ith digit of the integer. The digits are ordered from most sig...

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...

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...

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]).

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...

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].

Candy

There are n children standing in a line. Each child is assigned a rating value given in the integer array ratings.

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...

Reverse Vowels of a String

Given a string s, reverse only all the vowels in the string and return it.

Find First and Last Position of Element in Sorted Array

Given an array of integers nums sorted in non-decreasing order, find the starting and ending position of a given target value.

Nth Digit

Given an integer n, return the nth digit of the infinite integer sequence [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, ...].

Assign Cookies

Assume you are an awesome parent and want to give your children some cookies. But, you should give each child at most one cookie.

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...

Longest Increasing Subsequence

Given an integer array nums, return the length of the longest strictly increasing subsequence.

Coin Change

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

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.

Count Primes

Given an integer n, return the number of prime numbers that are strictly less than n.

Pascal's Triangle

Given an integer numRows, return the first numRows of Pascal's triangle.

Contains Duplicate

Given an integer array nums, return true if any value appears at least twice in the array, and return false if every element is distinct.

Remove Element

Given an integer array nums and an integer val, remove all occurrences of val in nums in-place. The order of the elements may be changed. Then return the number...

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.

Peak Index in a Mountain Array

You are given an integer mountain array arr of length n where the values increase to a peak element and then decrease.

Max Consecutive Ones

Given a binary array nums, return the maximum number of consecutive 1's in the array.

Unique Paths

There is a robot on an m x n grid. The robot is initially located at the top-left corner (i.e., grid[0][0]). The robot tries to move to the bottom-right corner...

Majority Element II

Given an integer array of size n, find all elements that appear more than ⌊ n/3 ⌋ times.

Remove Duplicates from Sorted List

Given the head of a sorted linked list, delete all duplicates such that each element appears only once. Return the linked list sorted as well.

Is Subsequence

Given two strings s and t, return true if s is a subsequence of t, or false otherwise.

Reverse Linked List

Given the head of a singly linked list, reverse the list, and return the reversed list.

Perfect Number

A perfect number is a positive integer that is equal to the sum of its positive divisors, excluding the number itself. A divisor of an integer x is an integer t...

Sort Array by Increasing Frequency

Given an array of integers nums, sort the array in increasing order based on the frequency of the values. If multiple values have the same frequency, sort them...

Find the Winner of the Circular Game

There are n friends that are playing a game. The friends are sitting in a circle and are numbered from 1 to n in clockwise order. More formally, moving clockwis...

Next Greater Element I

The next greater element of some element x in an array is the first greater element that is to the right of x in the same array.

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...

Edit Distance

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

Rotate Image

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

Next Permutation

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

Basic Calculator II

Given a string s which represents an expression, evaluate this expression and return its value.

Pow(x, n)

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

Ugly Number II

An ugly number is a positive integer whose prime factors are limited to 2, 3, and 5.

Intersection of Two Linked Lists

Given the heads of two singly linked-lists headA and headB, return the node at which the two lists intersect. If the two linked lists have no intersection at al...

Group Anagrams

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

Department Top Three Salaries

Table: Employee

Kth Largest Element in an Array

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

How Many Numbers Are Smaller Than the Current Number

Given the array nums, for each nums[i] find out how many numbers in the array are smaller than it. That is, for each nums[i] you have to count the number of val...

Palindromic Substrings

Given a string s, return the number of palindromic substrings in it.

Min Cost Climbing Stairs

You are given an integer array cost where cost[i] is the cost of ith step on a staircase. Once you pay the cost, you can either climb one or two steps.

Truncate Sentence

A sentence is a list of words that are separated by a single space with no leading or trailing spaces. Each of the words consists of only uppercase and lowercas...

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...

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.

Make The String Great

Given a string s of lower and upper case English letters.

Maximum Depth of Binary Tree

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

01 Matrix

Given an m x n binary matrix mat, return the distance of the nearest 0 for each cell.

Average Value of Even Numbers That Are Divisible by Three

Given an integer array nums of positive integers, return the average value of all even integers that are divisible by 3.

Integer to Roman

Seven different symbols represent Roman numerals with the following values:

Single Number II

Given an integer array nums where every element appears three times except for one, which appears exactly once. Find the single element and return it.

Daily Temperatures

Given an array of integers temperatures represents the daily temperatures, return an array answer such that answer[i] is the number of days you have to wait aft...

Search a 2D Matrix

You are given an m x n integer matrix matrix with the following two properties:

Count Pairs Whose Sum is Less than Target

Given a 0-indexed integer array nums of length n and an integer target, return the number of pairs (i, j) where 0 <= i < j < n and nums[i] + nums[j] < target.

Substrings of Size Three with Distinct Characters

A string is good if there are no repeated characters.

Count Operations to Obtain Zero

You are given two non-negative integers num1 and num2.

Number of Days Between Two Dates

Write a program to count the number of days between two dates.

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.

Excel Sheet Column Title

Given an integer columnNumber, return its corresponding column title as it appears in an Excel sheet.

Second Highest Salary

Table: Employee

Find Original Array From Doubled Array

An integer array original is transformed into a doubled array changed by appending twice the value of every element in original, and then randomly shuffling the...

N-th Tribonacci Number

The Tribonacci sequence Tn is defined as follows: