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https://leetcode.com/problems/median-of-two-sorted-arrays/description/There are two sorted arrays nums1 and nums2 of size m and n respectively.Find the median of the two sorted arrays. The overall run...

https://leetcode.com/problems/longest-palindromic-substring/description/Given a string s, find the longest palindromic substring in s. You may assume that the maximum length of s is 1000.Input: "babad...

The string "PAYPALISHIRING" is written in a zigzag pattern on a given number of rows like this: (you may want to display this pattern in a fixed font for better legibility)P A H NA P L S I I G...

https://leetcode.com/problems/reverse-integer/description/Given a 32-bit signed integer, reverse digits of an integer.Input: 123Output: 321Input: -123Output: -321Input: 120Output: 21Note:Assume we ...

https://leetcode.com/problems/string-to-integer-atoi/description/Implement atoi which converts a string to an integer.The function first discards as many whitespace characters as necessary until the f...

https://leetcode.com/problems/palindrome-number/description/Determine whether an integer is a palindrome. An integer is a palindrome when it reads the same backward as forward.Input: 121Output: trueI...

https://leetcode.com/problems/two-sum/description/Given an array of integers, return indices of the two numbers such that they add up to a specific target.You may assume that each input would have exa...

https://leetcode.com/problems/add-two-numbers/description/You are given two non-empty linked lists representing two non-negative integers. The digits are stored in reverse order and each of their node...

https://leetcode.com/problems/longest-substring-without-repeating-characters/description/Given a string, find the length of the longest substring without repeating characters.Given  "abcabcbb", the an...

https://leetcode.com/problems/regular-expression-matching/description/Given an input string (s) and a pattern (p), implement regular expression matching with support for '.' and '*'.'.' Matches any si...

https://leetcode.com/problems/container-with-most-water/description/Given n non-negative integers a1, a2, ..., an, where each represents a point at coordinate (i, ai). n vertical lines are drawn such ...

https://leetcode.com/problems/integer-to-roman/description/Roman numerals are represented by seven different symbols: I, V, X, L, C, D and M.Symbol ValueI 1V 5X ...

https://leetcode.com/problems/roman-to-integer/description/Roman numerals are represented by seven different symbols: I, V, X, L, C, D and M.Symbol ValueI 1V 5X ...

https://leetcode.com/problems/longest-common-prefix/description/Write a function to find the longest common prefix string amongst an array of strings.If there is no common prefix, return an empty stri...

https://leetcode.com/problems/3sum/description/Given an array nums of n integers, are there elements a, b, c in nums such that a + b + c = 0? Find all unique triplets in the array which gives the sum ...

https://leetcode.com/problems/3sum-closest/description/Given an array nums of n integers and an integer target, find three integers in nums such that the sum is closest to target. Return the sum of th...

https://leetcode.com/problems/letter-combinations-of-a-phone-number/description/Given a string containing digits from 2-9 inclusive, return all possible letter combinations that the number could repre...

https://leetcode.com/problems/remove-duplicates-from-sorted-array/description/Given a sorted array nums, remove the duplicates in-place such that each element appear only once and return the new len...

https://leetcode.com/problems/remove-element/description/Given an array nums and a value val, remove all instances of that value in-place and return the new length.Do not allocate extra space for ...

https://leetcode.com/problems/implement-strstr/description/Implement strStr().Return the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.Example 1:...

https://leetcode.com/problems/divide-two-integers/description/Given two integers dividend and divisor, divide two integers without using multiplication, division and mod operator.Return the quotie...

https://leetcode.com/problems/4sum/description/Given an array nums of n integers and an integer target, are there elements a, b, c, and d in nums such that a + b + c + d = target? Find all unique qu...

https://leetcode.com/problems/remove-nth-node-from-end-of-list/description/Given a linked list, remove the n-th node from the end of list and return its head.Example:Given linked list: 1->2-...

https://leetcode.com/problems/valid-parentheses/description/Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.An input string is...

https://leetcode.com/problems/merge-two-sorted-lists/description/Merge two sorted linked lists and return it as a new list. The new list should be made by splicing together the nodes of the first tw...

https://leetcode.com/problems/generate-parentheses/description/Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses.For example, given n = 3, a so...

https://leetcode.com/problems/multiply-strings/description/Given two non-negative integers num1 and num2 represented as strings, return the product of num1 and num2, also represented as a string.E...

https://leetcode.com/problems/substring-with-concatenation-of-all-words/description/You are given a string, s, and a list of words, words, that are all of the same length. Find all starting indices ...

https://leetcode.com/problems/wildcard-matching/description/Given an input string (s) and a pattern (p), implement wildcard pattern matching with support for '?' and '*'.'?' Matches any single ch...

https://leetcode.com/problems/jump-game-ii/description/Given an array of non-negative integers, you are initially positioned at the first index of the array.Each element in the array represents yo...

https://leetcode.com/problems/permutations/description/Input: [1,2,3]Output:[ [1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], [3,2,1]]import copyclass Solution(object): def perm...

https://leetcode.com/problems/permutations-ii/description/Given a collection of numbers that might contain duplicates, return all possible unique permutations.Example:Input: [1,1,2]Output:[ ...

https://leetcode.com/problems/rotate-image/description/You are given an n x n 2D matrix representing an image.Rotate the image by 90 degrees (clockwise).Note:You have to rotate the image in-pl...

https://leetcode.com/problems/group-anagrams/description/Given an array of strings, group anagrams together.Example:Input: ["eat", "tea", "tan", "ate", "nat", "bat"],Output:[ ["ate

https://leetcode.com/problems/powx-n/description/Implement pow(x, n), which calculates x raised to the power n (xn).Example 1:Input: 2.00000, 10Output: 1024.00000Example 2:Input: 2.10000...

https://leetcode.com/problems/next-permutation/description/Implement next permutation, which rearranges numbers into the lexicographically next greater permutation of numbers.If such arrangement i...

https://leetcode.com/problems/n-queens/description/The n-queens puzzle is the problem of placing n queens on an n×n chessboard such that no two queens attack each other.Given an integer n, retur...

https://leetcode.com/problems/n-queens-ii/description/The n-queens puzzle is the problem of placing n queens on an n×n chessboard such that no two queens attack each other.Given an integer n, re...

https://leetcode.com/problems/maximum-subarray/description/Given an integer array nums, find the contiguous subarray (containing at least one number) which has the largest sum and return its sum.E...

https://leetcode.com/problems/spiral-matrix/description/Given a matrix of m x n elements (m rows, n columns), return all elements of the matrix in spiral order.Example 1:Input:[ [ 1, 2, 3 ],...