[프로그래머스] 올바른 괄호

#include<string>
#include <stack>
#include <iostream>

using namespace std;

bool solution(string s)
{
    bool answer = true;
    stack <char> st;
    if(s[0] == '('){
        //st.push(s[0]);
        for(int i =0; i < s.length(); i++){
            char ss = s[i];
            if(ss == '(')
                st.push(ss);
            else{
                if(!st.empty())
                    st.pop();
                else{
                    answer = false;
                    break;
                }
            }
            if(st.empty())
                answer = true;
            else
                answer = false;
         }
    }
    else
        answer = false;
    
    return answer;
}