原文链接: https://leetcode-cn.com/problems/missing-number 英文原文Given an array nums containing n distinct numbers in the range [0, n], return the only number in the range that is missing from the array. Example 1: Input: nums = [3,0,1] Output: 2 Explanatio…

原文链接: https://leetcode-cn.com/problems/integer-to-english-words 英文原文Convert a non-negative integer num to its English words representation. Example 1: Input: num = 123 Output: "One Hundred Twenty Three" Example 2: Input: num = 12345 Output: "Twelve T…

原文链接: https://leetcode-cn.com/problems/h-index 英文原文Given an array of integers citations where citations[i] is the number of citations a researcher received for their ith paper, return compute the researcher's h-index. According to the definition of h…

原文链接: https://leetcode-cn.com/problems/h-index-ii 英文原文Given an array of integers citations where citations[i] is the number of citations a researcher received for their ith paper and citations is sorted in an ascending order, return compute the resea…

原文链接: https://leetcode-cn.com/problems/first-bad-version 英文原文You are a product manager and currently leading a team to develop a new product. Unfortunately, the latest version of your product fails the quality check. Since each version is developed b…

原文链接: https://leetcode-cn.com/problems/perfect-squares 英文原文Given an integer n, return the least number of perfect square numbers that sum to n. A perfect square is an integer that is the square of an integer; in other words, it is the product of some…

原文链接: https://leetcode-cn.com/problems/expression-add-operators 英文原文Given a string num that contains only digits and an integer target, return all possibilities to insert the binary operators '+', '-', and/or '*' between the digits of num so that the…

原文链接: https://leetcode-cn.com/problems/move-zeroes 英文原文Given an integer array nums, move all 0's to the end of it while maintaining the relative order of the non-zero elements. Note that you must do this in-place without making a copy of the array. E…

原文链接: https://leetcode-cn.com/problems/peeking-iterator 英文原文Design an iterator that supports the peek operation on an existing iterator in addition to the hasNext and the next operations. Implement the PeekingIterator class: PeekingIterator(Iterator<…

原文链接: https://leetcode-cn.com/problems/find-the-duplicate-number 英文原文Given an array of integers nums containing n + 1 integers where each integer is in the range [1, n] inclusive. There is only one repeated number in nums, return this repeated number…

原文链接: https://leetcode-cn.com/problems/game-of-life 英文原文According to Wikipedia's article: "The Game of Life, also known simply as Life, is a cellular automaton devised by the British mathematician John Horton Conway in 1970." The board is made up of …

原文链接: https://leetcode-cn.com/problems/word-pattern 英文原文Given a pattern and a string s, find if s follows the same pattern. Here follow means a full match, such that there is a bijection between a letter in pattern and a non-empty word in s. Example …

原文链接: https://leetcode-cn.com/problems/nim-game 英文原文You are playing the following Nim Game with your friend: Initially, there is a heap of stones on the table. You and your friend will alternate taking turns, and you go first. On each turn, the perso…

原文链接: https://leetcode-cn.com/problems/find-median-from-data-stream 英文原文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 middle values. For exam…

原文链接: https://leetcode-cn.com/problems/serialize-and-deserialize-binary-tree 英文原文Serialization is the process of converting a data structure or object into a sequence of bits so that it can be stored in a file or memory buffer, or transmitted across …

原文链接: https://leetcode-cn.com/problems/bulls-and-cows 英文原文You are playing the Bulls and Cows game with your friend. You write down a secret number and ask your friend to guess what the number is. When your friend makes a guess, you provide a hint wit…

原文链接: https://leetcode-cn.com/problems/longest-increasing-subsequence 英文原文Given an integer array nums, return the length of the longest strictly increasing subsequence. A subsequence is a sequence that can be derived from an array by deleting some or…

原文链接: https://leetcode-cn.com/problems/remove-invalid-parentheses 英文原文Given a string s that contains parentheses and letters, remove the minimum number of invalid parentheses to make the input string valid. Return all the possible results. You may re…

原文链接: https://leetcode-cn.com/problems/range-sum-query-immutable 英文原文Given an integer array nums, handle multiple queries of the following type: Calculate the sum of the elements of nums between indices left and right inclusive where left <= right. I…

原文链接: https://leetcode-cn.com/problems/range-sum-query-2d-immutable 英文原文Given a 2D matrix matrix, handle multiple queries of the following type: Calculate the sum of the elements of matrix inside the rectangle defined by its upper left corner (row1, …

原文链接: https://leetcode-cn.com/problems/additive-number 英文原文Additive number is a string whose digits can form additive sequence. A valid additive sequence should contain at least three numbers. Except for the first two numbers, each subsequent number …

原文链接: https://leetcode-cn.com/problems/range-sum-query-mutable 英文原文Given an integer array nums, handle multiple queries of the following types: Update the value of an element in nums. Calculate the sum of the elements of nums between indices left and…

原文链接: https://leetcode-cn.com/problems/best-time-to-buy-and-sell-stock-with-cooldown 英文原文You are given an array prices where prices[i] is the price of a given stock on the ith day. Find the maximum profit you can achieve. You may complete as many tra…

原文链接: https://leetcode-cn.com/problems/minimum-height-trees 英文原文A tree is an undirected graph in which any two vertices are connected by exactly one path. In other words, any connected graph without simple cycles is a tree. Given a tree of n nodes la…

原文链接: https://leetcode-cn.com/problems/burst-balloons 英文原文You are given n balloons, indexed from 0 to n - 1. Each balloon is painted with a number on it represented by an array nums. You are asked to burst all the balloons. If you burst the ith ballo…

原文链接: https://leetcode-cn.com/problems/count-of-smaller-numbers-after-self 英文原文You are given an integer array nums and you have to return a new counts array. The counts array has the property where counts[i] is the number of smaller elements to the r…

原文链接: https://leetcode-cn.com/problems/remove-duplicate-letters 英文原文Given a string s, remove duplicate letters so that every letter appears once and only once. You must make sure your result is the smallest in lexicographical order among all possible…

原文链接: https://leetcode-cn.com/problems/maximum-product-of-word-lengths 英文原文Given a string array words, return the maximum value of length(word[i]) * length(word[j]) where the two words do not share common letters. If no such two words exist, return 0…

原文链接: https://leetcode-cn.com/problems/bulb-switcher 英文原文There are n bulbs that are initially off. You first turn on all the bulbs, then you turn off every second bulb. On the third round, you toggle every third bulb (turning on if it's off or turnin…

原文链接: https://leetcode-cn.com/problems/create-maximum-number 英文原文You are given two integer arrays nums1 and nums2 of lengths m and n respectively. nums1 and nums2 represent the digits of two numbers. You are also given an integer k. Create the maximu…