[C++] 괄호 - 9012

#include <iostream>
#include <vector>
using namespace std;

class CheckStr
{
public:
	CheckStr(string str) : _str(str)
	{
		int len = _str.length();
		int nL = 0;
		int nR = 0;

		for (int i = 0; i < len; i++)
		{
			if (str[i] == ')')
			{
				nR++;
				if (nL < nR)
				{
					isOperate = false;
					return;
				}
			}
			if (str[i] == '(')
				nL++;
		}
		
		if (nL == nR)
			isOperate = true;
	}
public:
	string _str;
	bool isOperate = false;
};

int main()
{
	int N = 0;
	string str = "";
	vector<CheckStr> v;
	
	cin >> N;

	for (int i = 0; i < N; i++)
	{
		cin >> str;
		v.push_back(CheckStr(str));
	}
	
	for (int i = 0; i < N; i++)
	{
		if (v[i].isOperate == true)
			cout << "YES" << endl;
		else
			cout << "NO" << endl;
	}
	return 0;

}