Leetcode 0003: Longest Substring Without Repeating Characters
题目描述：Given a string s, find the length of the longest substring without repeating characters.Example 1:Input: s = “abcabcbb”Output: 3Explanation: The answer is “abc”, with the length of 3.Example 2:Input: s = “bbbbb”Output: 1Explanation: The
Leetcode 0004: Median of Two Sorted Arrays
题目描述：Given two sorted arrays nums1 and nums2 of size m and n respectively, return the median of the two sorted arrays.Follow up: The overall run time complexity should be O(log (m+n)).Example 1:Input: nums1 = [1,3], nums2 = [2]Output: 2.00000Expla
Leetcode 题目汇总
Leetcode 题目汇总持续更新题号题目难度0001两数之和 Two Sum简单0002两数相加 Add Two Numbers中等0003无重复字符的最长子串 Longest Substring Without Repeating Characters中等0004寻找两个正序数组的中位数 Median of Two Sorted Arrays困难...
Leetcode 0005: Longest Palindromic Substring
题目描述：Given a string s, return the longest palindromic substring in s.Example 1:Input: s = “babad”Output: “bab”Note: “aba” is also a valid answer.Example 2:Input: s = “cbbd”Output: “bb”Example 3:Input: s = “a”Output: “a”Example 4:Input
Leetcode 0006: ZigZag Conversion
题目描述：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 GY _ I _ R _ _And then read line by line:
Leetcode 0007: Reverse Integer
题目描述：Given a signed 32-bit integer x, return x with its digits reversed. If reversing x causes the value to go outside the signed 32-bit integer range [-231, 231 - 1], then return 0.Assume the environment does not allow you to store 64-bit integers (sig
Leetcode 0215: Kth Largest Element in an Array
题目描述：Find the kth largest element in an unsorted array. Note that it is the kth largest element in the sorted order, not the kth distinct element.Example 1:Input: [3,2,1,5,6,4] and k = 2Output: 5Example 2:Input: [3,2,3,1,2,4,5,5,6] and k = 4Out
Leetcode 0008: String to Integer (atoi)
题目描述：Implement the myAtoi(string s) function, which converts a string to a 32-bit signed integer (similar to C/C++'s atoi function).The algorithm for myAtoi(string s) is as follows:Read in and ignore any leading whitespace.Check if the next character
Leetcode 0009: Palindrome Number
题目描述：Given an integer x, return true if x is palindrome integer.An integer is a palindrome when it reads the same backward as forward. For example, 121 is palindrome while 123 is not.Note:Input: x = 121Output: trueExample 1:Input: s = “42”Outp
Leetcode 0011: Container With Most Water
题目描述：Given an input string (s) and a pattern §, implement regular expression matching with support for ‘.’ and ‘’ where:‘.’ Matches any single character.'’ Matches zero or more of the preceding element.The matching should cover the entire input st
Leetcode 0216: Combination Sum III
题目描述：Find all valid combinations of k numbers that sum up to n such that the following conditions are true:Only numbers 1 through 9 are used.Each number is used at most once.Return a list of all possible valid combinations. The list must not contain t
Leetcode 0010: Regular Expression Matching
题目描述：Given an input string s and a pattern p, implement regular expression matching with support for ’ . ’ and ‘ * ‘ where:‘.’ Matches any single character.‘*’ Matches zero or more of the preceding element.The matching should cover the entire inp
Leetcode 0218: The Skyline Problem
题目描述：A city’s skyline is the outer contour of the silhouette formed by all the buildings in that city when viewed from a distance. Given the locations and heights of all the buildings, return the skyline formed by these buildings collectively.The geom
Leetcode 0220: Contains Duplicate III
题目描述：Given an array of integers, find out whether there are two distinct indices i and j in the array such that the absolute difference between nums[i] and nums[j] is at most t and the absolute difference between i and j is at most k.中文描述：Example 1:
Leetcode 0221: Maximal Square
题目描述：Given an m x n binary matrix filled with 0’s and 1’s, find the largest square containing only 1’s and return its area.Example 1:Input: matrix = [[“1”,“0”,“1”,“0”,“0”],[“1”,“0”,“1”,“1”,“1”],[“1”,“1”,“1”,“1”,“1”],[“1”,“0”,“0”,“1”,“0”]]Output: 4
Leetcode 0222: Count Complete Tree Nodes
题目描述：Given the root of a complete binary tree, return the number of the nodes in the tree.According to Wikipedia, every level, except possibly the last, is completely filled in a complete binary tree, and all nodes in the last level are as far left as p
Leetcode 0224: Basic Calculator
题目描述：Given a string s representing an expression, implement a basic calculator to evaluate it.Example 1:Input: s = “1 + 1”Output: 2Example 2:Input: s = " 2-1 + 2 "Output: 3Example 3:Input: s = " 2-1 + 2 "Output: 3Constraints:1 <= s.
Leetcode 0229: Majority Element II
题目描述：Given an integer array of size n, find all elements that appear more than ⌊ n/3 ⌋ times.Follow-up: Could you solve the problem in linear time and in O(1) space?Example 1:Input: nums = [3,2,3]Output: [3]Example 2:Input: nums = [1]Output: [
Leetcode 0225: Implement Stack using Queues
题目描述：Implement a last in first out (LIFO) stack using only two queues. The implemented stack should support all the functions of a normal queue (push, top, pop, and empty).Implement the MyStack class:void push(int x) Pushes element x to the top of the
Leetcode 0250: Count Univalue Subtrees
题目描述：Given the root of a binary tree, return the number of uni-value subtrees.A uni-value subtree means all nodes of the subtree have the same value.Example 1:Input: root = [5,1,5,5,5,null,5]Output: 4Example 2:Input: root = [5,5,5,5,5,null,5]
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