链接: https://oj.leetcode.com/problems/valid-parentheses/
括号匹配。用栈
class Solution { public: bool isValid(string s) { stack<char> sta; int n=s.size(); for(int i=0;i<n;i++) { char t=s[i]; if(t=='('||t=='['||t=='{') sta.push(t); else { if(sta.empty()) return false; if((!sta.empty())&&( (sta.top()=='('&&t==')')||(sta.top()=='['&&t==']')||(sta.top()=='{'&&t=='}'))) { sta.pop(); continue; } if((!sta.empty())&&sta.top()!=t) return false; } } if(sta.empty()) return true; else return false; } };
天下武功,唯快不破