Cognizant Coding Interview Questions

Palindrome Number

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

Count Subarrays Of Length Three With A Condition

Given an integer array nums, return the number of subarrays of length 3 such that the sum of the first and third numbers equals exactly half of the second numbe...

Smallest Value of the Rearranged Number

You are given an integer num. Rearrange the digits of num such that its value is minimized and it does not contain any leading zeros.

Two Sum

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

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...

Valid Anagram

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

Longest Palindromic Substring

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

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...

Maximum Subarray

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

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 Common Prefix

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

Valid Parentheses

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

Second Highest Salary

Table: Employee

Product Sales Analysis I

Table: Sales

Managers with at Least 5 Direct Reports

Table: Employee

Count Primes

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

Students and Examinations

Table: Students

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.

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...

Merge Two Sorted Lists

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

Search Insert Position

Given a sorted array of distinct integers and a target value, return the index if the target is found. If not, return the index where it would be if it were ins...

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.

Fizz Buzz

Given an integer n, return a string array answer (1-indexed) where:

Rising Temperature

Table: Weather

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.

Longest Substring Without Repeating Characters

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

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...

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...

Happy Number

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