leetcode vs hackerrank

Leetcode Note: 3Sum, leetcode note 3sum I. Description Ii. problem-solving skills This question is similar to the Two Sum of another question. However, this question is used to search for three numbers in the array so that the Sum is 0. At the same time, it is required that the three numbers only appear once. If we only need to use the brute force algorithm, the time complexity is O (n ^ 3), and it is dif

LeetCode summary, leetcodeThis article mainly introduces several questions about kSum in LeetCode. The main requirement is to find the number of k in the array and whether it can reach the target value. LeetCode:Two Sum3Sum3Sum Closest4SumFirst of all, starting with Two Sum, this question provides the basic idea of the next k> 2 questions and is also the most frequently tested questions (Amazon's interview

[LeetCode] Best Time to Buy and Buy Stock I II III IV problem solving report, leetcode=Best Time to Buy and Buy Stock I Question:An array is used to represent the daily price of the stock, and the number of I in the array indicates the price of the stock on the day I. If only one transaction is allowed, that is, only one stock can be bought and sold for the maximum benefit. Analysis:Dynamic Programming Meth

[LeetCode-interview algorithm classic-Java implementation] [009-Palindrome Number (Number of replies)], leetcode -- java [009-Palindrome Number (Number of replies )][LeetCode-interview algorithm classic-Java implementation] [directory indexes for all questions]Original question Determine whether an integer is a palindrome. Do this without extra space. Theme Deter

[LeetCode-interview algorithm classic-Java implementation] [017-Letter Combinations of a Phone Number (word Combinations on Phone numbers)], Chapter 9 leetcode [017-Letter Combinations of a Phone Number (a word combination on the Phone Number )][LeetCode-interview algorithm classic-Java implementation] [directory indexes for all questions]Original question Given

[LeetCode-interview algorithm classic-Java implementation] [013-Roman to Integer (Roman to Integer)], leetcode -- java [013-Roman to Integer (Roman to Integer )][LeetCode-interview algorithm classic-Java implementation] [directory indexes for all questions]Original question Given a roman numeral, convert it to an integer.Input is guaranteed to be within the range

[LeetCode-interview algorithm classic-Java implementation] [219-Contains Duplicate II (including Duplicate element II)], leetcode -- java [219-Contains Duplicate II (including Duplicate element II )][LeetCode-interview algorithm classic-Java implementation] [directory indexes for all questions]Download the Code [https://github.com/wang-jun-chao]Original question

[LeetCode-interview algorithm classic-Java implementation] [216-Combination Sum III (Sum of the number of combinations)], leetcode -- java [216-Combination Sum III (Sum of the number of combinations )][LeetCode-interview algorithm classic-Java implementation] [directory indexes for all questions]Download the Code [https://github.com/wang-jun-chao]Original questio

[LeetCode-interview algorithm classic-Java implementation] [062-Unique Paths (Unique path)], leetcode -- java [062-Unique Paths (Unique path )][LeetCode-interview algorithm classic-Java implementation] [directory indexes for all questions]Original question A robot is located at the top-left corner ofm x nGrid (marked 'start' in the dimo-below ).The robot can only

[LeetCode-interview algorithm classic-Java implementation] [058-Length of Last Word (Length of the Last Word)], leetcode -- java [058-Length of Last Word (Length of the Last Word )][LeetCode-interview algorithm classic-Java implementation] [directory indexes for all questions]Original question Given a string s consists of upper/lower-case alphabets and empty spac

[LeetCode-interview algorithm classic-Java implementation] [075-Sort Colors (Color Sorting)], leetcode -- java [075-Sort Colors (Color Sorting )][LeetCode-interview algorithm classic-Java implementation] [directory indexes for all questions]Original question Given an array with n objects colored red, white or blue, sort them so that objects of the same color are

[LeetCode-interview algorithm classic-Java implementation] [098-Validate Binary Search Tree (verify Binary Search Tree)], leetcode -- java [098-Validate Binary Search Tree (verify Binary Search Tree )][LeetCode-interview algorithm classic-Java implementation] [directory indexes for all questions]Original question Given a binary tree, determine if it is a valid bi

[LeetCode-interview algorithm classic-Java implementation] [067-Add Binary (Binary addition)], leetcode -- java [067-Add Binary (Binary addition )][LeetCode-interview algorithm classic-Java implementation] [directory indexes for all questions]Original question Given two binary strings, return their sum (also a binary string ).For example,A ="11" B ="1" Return"100

[LeetCode-interview algorithm classic-Java implementation] [064-Minimum Path Sum (Minimum Path and)], leetcode -- java [064-Minimum Path Sum (Minimum Path and )][LeetCode-interview algorithm classic-Java implementation] [directory indexes for all questions]Original question Given a m x n grid filled with non-negative numbers, find a path from top left to bottom r

[LeetCode-interview algorithm classic-Java implementation] [101-Symmetric Tree], leetcode -- java [101-Symmetric Tree )][LeetCode-interview algorithm classic-Java implementation] [directory indexes for all questions]Original question Given a binary tree, check whether it is a mirror of itself (ie, shortric around its center ).For example, this binary tree is unsu

[LeetCode-interview algorithm classic-Java implementation] [079-Word Search], leetcode -- java [079-Word Search )][LeetCode-interview algorithm classic-Java implementation] [directory indexes for all questions]Original question Given a 2D board and a word, find if the word exists in the grid.The word can be constructed from letters of sequentially adjacent cell,

[LeetCode-interview algorithm classic-Java implementation] [070-Climbing Stairs (Stairs)], leetcode -- java [070-Climbing Stairs )][LeetCode-interview algorithm classic-Java implementation] [directory indexes for all questions]Original question You are climbing a stair case. It takes n steps to reach to the top.Each time you can either climb 1 or 2 steps. In how

Leetcode 1, leetcodeQuestion Given an array of integers, returnindicesof the two numbers such that they add up to a specific target.You may assume that each input would haveexactlyone solution.Example:Given nums = [2, 7, 11, 15], target = 9,Because nums[0] + nums[1] = 2 + 7 = 9,return [0, 1].Solution Public int [] TwoSum (int [] nums, int target) {# region solution 1, brute force cracking method int [] newInt = null; for (int I = 0; I Solution on OJ:

[Leetcode-easy] String to Integer (atoi), leetcode-easyatoi Requirement: String> integer * 1. First, discard the space before the string.* 2. Then there may be positive and negative signs (note that only one is taken. If there are multiple positive and negative signs, this string cannot be converted and 0 is returned. For example, there is a "+-2" in the test case ").* 3. The string can contain 0 ~ If a non

LeetCode -- Same Tree, leetcode -- sametreeQuestion: Given two binary trees, write a function to check if they are equal or not. Two binary trees are considered equal if they are structurally identical and the nodes have the same value.Solution: /*** Definition for binary tree * public class TreeNode {* int val; * TreeNode left; * TreeNode right; * TreeNode (int x) {val = x ;} *} */public class Solution