C++ 알고리즘 - 백준 9012 괄호

https://www.acmicpc.net/problem/9012

 

#include <iostream>
#include <string>
#include <stack>
#define endl "\n"

using namespace std;

int main(void) {
	// C++ Init
	ios::sync_with_stdio(false);
	cin.tie(NULL);

	int input;
	string str;
	char ch;
	cin >> input;
	cin.ignore();

	for (int i = 0; i < input; i++) {
		stack<char> st;
		getline(cin, str);
		
		for (int j = 0; j < str.size(); j++) {
			if (j == 0 && str[j] == ')') {
				cout << "NO" << endl;
				break;
			}

			if (str[j] == '(') {
				st.push(str[j]);
				continue;
			}
				
			
			if (str[j] == ')') {
				if (st.empty()) {
					cout << "NO" << endl;
					break;
				}

				ch = st.top();
				st.pop();

				if (ch == '(') {
					if (j == str.size() - 1 && st.empty()) {
						cout << "YES" << endl;
						break;
					}

					else continue;
				}	
			}
		}	

		if (!st.empty())
			cout << "NO" << endl;
	}
}