King来写代码的专栏

Tow SumGiven 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 exactly one solution.*Example: Given nums = [2

Longest Valid ParenthesesGiven a string containing just the characters ‘(’ and ‘)’, find the length of the longest valid (well-formed) parentheses substring.For “(()”, the longest valid parentheses sub

Median of Two Sorted ArraysThere are two sorted arrays nums1 and nums2 of size m and n respectively.Find the median of the two sorted arrays. The overall run time complexity should be O(log (m+n)).Exam

LeetCode动态规划归纳最近刷了很多动态规划的问题，归纳一下做动态规划的题的方法。动态规划很多题目是解决最多最少最大最小的问题。动态规划问题的基本做法是：确定递推量推出递推式确定边界在解决上述问题的同时，要时刻注意如何把全局的问题变成局部的（最优子结构），如何把前面计算过的子问题利用起来（重叠子问题）。下面把动态规划题分为几种类型。算种数的动态规划典型的题目包括：62.Unique Pa

Regular Expression MatchingImplement regular expression matching with support for ‘.’ and ‘*’.‘.’ Matches any single character. ‘*’ Matches zero or more of the preceding element.The matching should co

String to Integer (atoi)Implement atoi to convert a string to an integer.Hint: Carefully consider all possible input cases. If you want a challenge, please do not see below and ask yourself what are th

Reverse IntegerReverse digits of an integer.Example1: x = 123, return 321 Example2: x = -123, return -321**spoilers： Have you thought about this? Here are some good questions to ask before coding. B

ZigZag ConversionThe 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

Given a string S, find the longest palindromic substring in S. You may assume that the maximum length of S is 1000, and there exists one unique longest palindromic substring.解题思路：最长回文子串问题，很经典的问题。但一开始怎么

Longest Substring Without Repeating CharactersGiven a string, find the length of the longest substring without repeating characters.Examples:Given “abcabcbb”, the answer is “abc”, which the length is 3

Add Two NumbersYou are given two linked lists representing two non-negative numbers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and retur

Palindrome NumberDetermine whether an integer is a palindrome. Do this without extra space.解题思路：由于不能有额外的空间，所以可以参考上面的第7题倒转数字，根据回文的性质，倒转后的数字=原数字，注意倒转过程中不要使用额外的空间（除了必要的res）。代码如下： bool isPalindrome(int