题解

#include<bits/stdc++.h>
using namespace std;
int main(){
    stack<char> expression;  //创建一个栈
    string str;
    cin >> str;
    for (int i = 0 ; i < str.size() ; i++){
        if (str[i] == '(')
            expression.push(str[i]);  //入栈
        else if (str[i] == ')'){
            if (expression.empty()){
                cout << "NO";
                return 0;
            }
            expression.pop();  //出栈
        }
    }
    if (expression.empty())
        cout << "YES";
    else
        cout << "NO";
}