Capital One Coding Interview Questions

Simple Bank System

You have been tasked with writing a program for a popular bank that will automate all its incoming transactions (transfer, deposit, and withdraw). The bank has...

Spiral Matrix

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

Block Placement Queries

There exists an infinite number line, with its origin at 0 and extending towards the positive x-axis.

Text Justification

Given an array of strings words and a width maxWidth, format the text such that each line has exactly maxWidth characters and is fully (left and right) justifie...

Minimum Operations to Write the Letter Y on a Grid

You are given a 0-indexed n x n grid where n is odd, and grid[r][c] is 0, 1, or 2.

Count Alternating Subarrays

You are given a binary array nums.

Rotate Image

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

Four Divisors

Given an integer array nums, return the sum of divisors of the integers in that array that have exactly four divisors. If there is no such integer in the array,...

Count Operations to Obtain Zero

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

Simplify Path

You are given an absolute path for a Unix-style file system, which always begins with a slash '/'. Your task is to transform this absolute path into its simplif...

Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit

Given an array of integers nums and an integer limit, return the size of the longest non-empty subarray such that the absolute difference between any two elemen...

Split Message Based on Limit

You are given a string, message, and a positive integer, limit.

Rotating the Box

You are given an m x n matrix of characters boxGrid representing a side-view of a box. Each cell of the box is one of the following:

Number of Black Blocks

You are given two integers m and n representing the dimensions of a 0-indexed m x n grid.

Largest Rectangle in Histogram

Given an array of integers heights representing the histogram's bar height where the width of each bar is 1, return the area of the largest rectangle in the his...

Count Prefix and Suffix Pairs II

You are given a 0-indexed string array words.

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.

Number of Flowers in Full Bloom

You are given a 0-indexed 2D integer array flowers, where flowers[i] = [starti, endi] means the ith flower will be in full bloom from starti to endi (inclusive)...

Find the Length of the Longest Common Prefix

You are given two arrays with positive integers arr1 and arr2.

Remove Boxes

You are given several boxes with different colors represented by different positive numbers.

Coin Change

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

Word Search

Given an m x n grid of characters board and a string word, return true if word exists in the grid.

Number of Subarrays That Match a Pattern I

You are given a 0-indexed integer array nums of size n, and a 0-indexed integer array pattern of size m consisting of integers -1, 0, and 1.

Palindrome Number

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

Add Strings

Given two non-negative integers, num1 and num2 represented as string, return the sum of num1 and num2 as a string.

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.

Non-overlapping Intervals

Given an array of intervals intervals where intervals[i] = [starti, endi], return the minimum number of intervals you need to remove to make the rest of the int...

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 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...

Binary Tree Paths

Given the root of a binary tree, return all root-to-leaf paths in any order.

Word Search II

Given an m x n board of characters and a list of strings words, return all words on the board.

Get Biggest Three Rhombus Sums in a Grid

You are given an m x n integer matrix grid​​​.

Find Servers That Handled Most Number of Requests

You have k servers numbered from 0 to k-1 that are being used to handle multiple requests simultaneously. Each server has infinite computational capacity but ca...

Rotate Array

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

Valid Parentheses

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

Minimum Absolute Difference Between Elements With Constraint

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

Merge Two Sorted Lists

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

Roman to Integer

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

LRU Cache

Design a data structure that follows the constraints of a Least Recently Used (LRU) cache.

Count Prefix and Suffix Pairs I

You are given a 0-indexed string array words.

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.

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.

K-diff Pairs in an Array

Given an array of integers nums and an integer k, return the number of unique k-diff pairs in the array.

Number of Adjacent Elements With the Same Color

You are given an integer n representing an array colors of length n where all elements are set to 0's meaning uncolored. You are also given a 2D integer array q...