1- 问题描述 Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. The brackets must close in the correct order, "()" and "()[]{}" are all valid but "(]" and "(…

目录 题目链接 注意点 解法 小结 题目链接 Valid Parentheses - LeetCode 注意点 考虑输入为空的情况 解法 解法一:如果是'('.'{'.'['这三者就入栈,否则就判断栈是否为空和栈顶括号是否与之匹配.注意两个判断顺序不可以颠倒,不然会runtime error.时间复杂度为O(n) class Solution { public: bool isValid(string s) { stack<char> stk; for(auto &ch:s) { if…

题目: Given a string containing just the characters '(' and ')', find the length of the longest valid (well-formed) parentheses substring. For "(()", the longest valid parentheses substring is "()", which has length = 2. Another example…

Given a string containing just the characters '(' and ')', find the length of the longest valid (well-formed) parentheses substring. For "(()", the longest valid parentheses substring is "()", which has length = 2. Another example is &…

题目: Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. The brackets must close in the correct order, "()" and "()[]{}" are all valid but "(]" and "([)]&…

Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. An input string is valid if: Open brackets must be closed by the same type of brackets. Open brackets must be closed in the correct…

# -*- coding: utf8 -*-'''__author__ = 'dabay.wang@gmail.com' 20: Valid Parentheseshttps://oj.leetcode.com/problems/valid-parentheses/ Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is vali…

这星期听别人说在做LeetCode,让他分享一题来看看.试了感觉挺有意思,可以培养自己的思路,还能方便的查看优秀的解决方案.准备自己也开始. 解决方案通常有多种多样,我觉得把自己的解决思路记录下来,阶段性查看,一定能对自己有帮助. 这是我做的第一题,所以记录也从这题开始,之后尽力以简短的说明,描述出思路,方便以后能回顾到简介明了的记录. 20. Valid Parentheses Given a string containing just the characters '(', ')', '{…

Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. An input string is valid if: Open brackets must be closed by the same type of brackets. Open brackets must be closed in the correct…

20. 有效的括号 20. Valid Parentheses 题目描述 给定一个只包括 '(',')','{','}','[',']' 的字符串,判断字符串是否有效. 有效字符串需满足: 左括号必须用相同类型的右括号闭合. 左括号必须以正确的顺序闭合. 注意空字符串可被认为是有效字符串. LeetCode20. Valid Parentheses 示例 1: 输入: "()" 输出: true 示例 2: 输入: "()[]{}" 输出: true 示例 3: 输…