栈的应用：括号匹配(C++)

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

bool isValid(string s) {
    stack<char> st;
    for (auto x : s) {
        if (x == '[' || x == '(' || x == '{')
            st.push(x);
        else if (st.empty())
            return false; 
        else if ( (st.top() == '(' && x == ')') || (st.top () == '[' && x == ']') || (st.top() == '{' && x == '}') )
            st.pop();
        else
            return false;
    }
    return st.empty();
}


int main() {
    string s;
    cin >> s;
    cout << isValid(s) << endl;
    return 0;
}