Top 100 Liked DSA Questions

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

Given an integer array nums and an integer k, return the k most frequent elements...

Given an integer array nums, return an array answer such that answer[i] is equal ...

Determine if a 9 x 9 Sudoku board is valid. Only the filled cells need to be validated according to the fol...

Design an algorithm to encode a list of strings to a single string. The encoded string is then sent over the network and...

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

A phrase is a palindrome if, after converting all uppercase letters into lowercase letters and removing...

Given an integer array nums, return all the triplets [nums[i], nums[j], nums[k]] such that ...

You are given an integer array height of length n. There are n vertical lines dra...

Given n non-negative integers representing an elevation map where the width of each bar is 1, ...

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

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

You are given a string s and an integer k. You can choose any character of the string and chan...

Given two strings s and t of lengths m and n respectively, return th...

Given two strings s and p, return an array of all the start indices of p's anagra...

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

Suppose an array of length n sorted in ascending order is rotated between 1 a...

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

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

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

You are given an array of integers nums, there is a sliding window of size k which is moving f...

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

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

You are given the head of a singly linked-list. The list can be represented as: L0 → L1 → … → Ln-1 → Ln...

Given the head of a linked list, remove the nth node from the end of the list and return its h...

A linked list of length n is given such that each node contains an additional random pointer, which could p...

You are given two non-empty linked lists representing two non-negative integers. The digits are stored ...

Given head, the head of a linked list, determine if the linked list has a cycle in it. There is a ...

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

Design a data structure that follows the constraints of a ...

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

Given a string s containing just the characters '(', ')', '{', ...

Design a stack that supports push, pop, top, and retrieving the minimum element in constant time. Implement the...

You are given an array of strings tokens that represents an arithmetic expression in a ...

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

Given an array of integers temperatures represents the daily temperatures, return an array answer...

There are n cars going to the same destination along a one-lane road. The destination is target...

Given an array of integers heights representing the histogram's bar height where the width of each bar is ...

You have a browser of your own. You start on the homepage, and you can visit ...

TinyURL is a URL shortening service where you enter a URL such as https://leetcode.com/problems/design-tinyurl...

Given an encoded string, return its decoded string. The encoding rule is: k[encoded_string], where...

Given a characters array tasks, representing the tasks a CPU needs to do, where each letter represents a di...

Given the root of a binary tree, invert the tree, and return its root. Company Tags:...

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

Given the roots of two binary trees p and q, write a function to check if they are the same or...

Given the roots of two binary trees root and subRoot, return true if there is a s...

Given a binary search tree (BST), find the lowest common ancestor (LCA) node of two given nodes in the BST. Acc...

Given the root of a binary tree, return the level order traversal of its nodes' values. (i.e., from left to...

Given the root of a binary tree, imagine yourself standing on the right side of it, return...

Given the root of a binary tree, determine if it is a valid binary search tree (BST). A va...

Given the root of a binary search tree, and an integer k, return the kth smallest...

Given two integer arrays preorder and inorder where preorder is the preorder trav...

A path in a binary tree is a sequence of nodes where each pair of adjacent nodes in the sequence has an...

Serialization is the process of converting a data structure or object into a sequence of bits so that it can be stored i...

Given two integer arrays inorder and postorder where inorder is the inorder trave...

You have n binary tree nodes numbered from 0 to n - 1 where node i h...

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

You are climbing a staircase. It takes n steps to reach the top. Each time you can either climb 1 ...

You are given an integer array coins representing coins of different denominations and an integer amo...

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

Given two strings text1 and text2, return the length of their longest common subsequen...

Given a string s and a dictionary of strings wordDict, return true if s...

Given an array of distinct integers candidates and a target integer target, r...

You are a professional robber planning to rob houses along a street. Each house has a certain amount of money stashed, t...

You are a professional robber planning to rob houses along a street. Each house has a certain amount of money stashed. A...

A message containing letters from A-Z is being encoded to numbers using the following mapping: 'A' -> 1 ...

There is a robot on an m x n grid. The robot is initially located at the top-left corner (...

You are given an integer array nums. You are initially positioned at the array's first index...

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

Given a collection of candidate numbers (candidates) and a target number (target), find all un...

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

Given an array nums of distinct integers, return all the possible permutations. You can return the answer i...

The n-queens puzzle is the problem of placing n chess queens on an n x n ches...

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

Given an m x n integers matrix, return the length of the longest increasing path in matr...

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

Given a string s, return the number of palindromic substrings in it. A string is a palindrome when it reads the...

Given an array of distinct integers nums and a target integer target, return ...

You are given an integer array coins representing coins of different denominations and an integer amo...

You are given a 0-indexed array of integers nums of length n. You are initial...

You are given an integer array nums and an integer target. You want to build an ...

Given strings s1, s2, and s3, find whether s3 is formed by an interleaving of ...

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

Given an m x n 2D binary grid grid which represents a map of '1's (land) and ...

Given a reference of a node in a connected undirected graph, return a deep copy (clone...

There are a total of numCourses courses you have to take, labeled from 0 to numCourses -...

There are a total of numCourses courses you have to take, labeled from 0 to numCourses -...

There is an m x n rectangular island that borders both the Pacific Ocean and the A...

You are given an m x n grid where each cell can have one of three values: ...

A transformation sequence from word beginWord to endWord using a dictionary ...

In this problem, a tree is an undirected graph that is connected and has no cycles. You are gi...

You have a graph of n nodes labeled from 0 to n - 1. You are given an integer ...

Given a list of accounts where each element accounts[i] is a list of strings, where the first ...

You have a graph of n nodes. You are given an integer n and an array edges where ...

Given an array of intervals where intervals[i] = [starti, endi], merge all overlapping interva...

You are given an array of non-overlapping intervals intervals where intervals[i] = [starti, endi]...

Given an array of intervals intervals where intervals[i] = [starti, endi], return the minimum ...

Given an array of meeting time intervals where intervals[i] = [starti, endi], determine if a person could a...

Given an array of meeting time intervals intervals where intervals[i] = [starti, endi], return...

Given a m x n grid filled with non-negative numbers, find a path from top left to bottom right...

Given an array of strings words and an integer k, return the k most frequent stri...

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

Design and implement a data structure for a ...

There are n gas stations on a circular route, where the amount of gas at the i-th station is ...

Alice has some number of cards and she wants to rearrange the cards into groups of groupSize consecutive ca...

A triplet is an array of three integers. You are given a 2D integer array triplets, where ...

You are given a string s. We want to partition the string into as many parts as possible so that each lette...

A peak element is an element that is strictly greater than its neighbors. Given a 0-indexed in...

Given a non-empty array of integers nums, every element appears twice except for ...

Write a function that takes the binary representation of an unsigned integer and returns the number of '1' bits it has (...

Given an integer n, return an array ans of length n + 1 such that for each ...

Given an array nums containing n distinct numbers in the range [0, n], return the...

Given two integers a and b, return the sum of the two integers without using the operators + a...

There is a new alien language that uses the English alphabet. However, the order among the letters is unknown to you....

Implement the RandomizedSet class: bool insert(int val): Inserts an item ...

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

Given an m x n integer matrix matrix, if an element is 0, set its entire row and ...

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