e924: pC. 括號配對

#include<iostream>
#include<stack>
#define endl '\n'
using namespace std;
int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    int n;
    string str;
    cin >> n;
    for (int i = 0; i != n; i++) {
        stack<char> s;
        cin >> str;
        for (const auto& i : str)
            switch (i) {
            case ')':
                if (s.size() && s.top() == '(') s.pop();
                else {s.push(i); goto break2;}
                break;
            case ']':
                if (s.size() && s.top() == '[') s.pop();
                else {s.push(i); goto break2;}
                break;
            case '>':
                if (s.size() && s.top() == '<') s.pop();
                else {s.push(i); goto break2;}
                break;
            case '}':
                if (s.size() && s.top() == '{') s.pop();
                else {s.push(i); goto break2;}
                break;
            default:
                s.push(i);
            }
break2:
        cout << "NY"[!s.size()] << endl;
    }
    return 0;
}