leetcode 921. Minimum Add to Make Parentheses Valid 使括号有效的最少添加-耗时100

Problem: 921. Minimum Add to Make Parentheses Valid 使括号有效的最少添加

耗时100%，栈若满足栈顶=='(‘当前==’)'则pop栈顶，否则push，最后返回栈的大小

Code

class Solution { public: int minAddToMakeValid(string s) { stack<char> tk; for(char & c : s) { if( tk.empty() == false && tk.top()=='(' && c==')' ) { tk.pop(); continue; } tk.push(c); } return tk.size(); } };