标签：lan put int ack size character 并且 return longest
Given a string containing just the characters ‘(‘ and ‘)‘, find the length of the longest valid (well-formed) parentheses substring.
Example 1:
Input: "(()"
Output: 2
Explanation: The longest valid parentheses substring is "()"
Example 2:
Input: ")()())" Output: 4 Explanation: The longest valid parentheses substring is"()()"
在给定字符串中找到子串,要求子串的括号是匹配的,并且长度最长.
解决办法,遍历这个字符串,把匹配的括号全部消除,用到的数据结构是stack.
stack里面保存索引,假如字符串整个括号都是匹配的,那么stack最终为空.
如果不为空,只要数出相邻的索引距离即可
class Solution { public: int longestValidParentheses(string s) { stack<int> st; for(int i=0;i<s.size();++i) { if(‘)‘==s[i]&&!st.empty()&&‘(‘==s[st.top()]) st.pop(); else st.push(i); } if(st.empty())return s.size(); int res=0; int tmp1=0,tmp2=s.size(); while(!st.empty()) { tmp1=st.top(); st.pop(); res=max(res, tmp2-tmp1-1); tmp2=tmp1; } res=max(res,tmp2); return res; } };
标签：lan put int ack size character 并且 return longest
原文地址：https://www.cnblogs.com/lychnis/p/11723300.html
