Coupang Coding Interview Questions

Subsets

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

Word Break

Given a string s and a dictionary of strings wordDict, return true if s can be segmented into a space-separated sequence of one or more dictionary words.

Decode String

Given an encoded string, return its decoded string.

LFU Cache

Design and implement a data structure for a Least Frequently Used (LFU) cache.

Find Pivot Index

Given an array of integers nums, calculate the pivot index of this array.

Range Module

A Range Module is a module that tracks ranges of numbers. Design a data structure to track the ranges represented as half-open intervals and query about them.

LRU Cache

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

Course Schedule

There are a total of numCourses courses you have to take, labeled from 0 to numCourses - 1. You are given an array prerequisites where prerequisites[i] = [ai, b...

Unique Paths II

You are given an m x n integer array grid. There is a robot initially located at the top-left corner (i.e., grid[0][0]). The robot tries to move to the bottom-r...

Design Twitter

Design a simplified version of Twitter where users can post tweets, follow/unfollow another user, and is able to see the 10 most recent tweets in the user's new...

Possible Bipartition

We want to split a group of n people (labeled from 1 to n) into two groups of any size. Each person may dislike some other people, and they should not go into t...

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...

Shopping Offers

In LeetCode Store, there are n items to sell. Each item has a price. However, there are some special offers, and a special offer consists of one or more differe...

Regular Expression Matching

Given an input string s and a pattern p, implement regular expression matching with support for '.' and '' where:

Longest Substring Without Repeating Characters

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

Longest Duplicate Substring

Given a string s, consider all duplicated substrings: (contiguous) substrings of s that occur 2 or more times. The occurrences may overlap.

Shortest Bridge

You are given an n x n binary matrix grid where 1 represents land and 0 represents water.

Remove K Digits

Given string num representing a non-negative integer num, and an integer k, return the smallest possible integer after removing k digits from num.

Find K Closest Elements

Given a sorted integer array arr, two integers k and x, return the k closest integers to x in the array. The result should also be sorted in ascending order.

Snapshot Array

Implement a SnapshotArray that supports the following interface:

Search a 2D Matrix

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

Basic Calculator II

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

Group Anagrams

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

Wildcard Matching

Given an input string (s) and a pattern (p), implement wildcard pattern matching with support for '?' and '' where:

Cheapest Flights Within K Stops

There are n cities connected by some number of flights. You are given an array flights where flights[i] = [fromi, toi, pricei] indicates that there is a flight...

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.

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.

Sliding Window Maximum

You are given an array of integers nums, there is a sliding window of size k which is moving from the very left of the array to the very right. You can only see...

Reorganize String

Given a string s, rearrange the characters of s so that any two adjacent characters are not the same.

Number of Atoms

Given a string formula representing a chemical formula, return the count of each atom.

Search a 2D Matrix II

Write an efficient algorithm that searches for a value target in an m x n integer matrix matrix. This matrix has the following properties:

Open the Lock

You have a lock in front of you with 4 circular wheels. Each wheel has 10 slots: '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'. The wheels can rotate freely...

Bus Routes

You are given an array routes representing bus routes where routes[i] is a bus route that the ith bus repeats forever.

Basic Calculator

Given a string s representing a valid expression, implement a basic calculator to evaluate it, and return the result of the evaluation.

Find Median from Data Stream

The median is the middle value in an ordered integer list. If the size of the list is even, there is no middle value, and the median is the mean of the two midd...

Kth Largest Element in an Array

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

Distinct Subsequences

Given two strings s and t, return the number of distinct subsequences of s which equals t.

Maximum Number of Tasks You Can Assign

You have n tasks and m workers. Each task has a strength requirement stored in a 0-indexed integer array tasks, with the ith task requiring tasks[i] strength to...

Split Strings by Separator

Given an array of strings words and a character separator, split each string in words by separator.

Pacific Atlantic Water Flow

There is an m x n rectangular island that borders both the Pacific Ocean and Atlantic Ocean. The Pacific Ocean touches the island's left and top edges, and the...

Increasing Triplet Subsequence

Given an integer array nums, return true if there exists a triple of indices (i, j, k) such that i < j < k and nums[i] < nums[j] < nums[k]. If no such indices e...