[프로그래머스] 쇠막대기

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

int solution(string arrangement) {
    int answer = 0;
    string before;
    string now;
    stack<char>left;
    left.push(arrangement[0]);
    for(int i= 1 ; i < arrangement.length(); i++){
        before = arrangement[i-1];
        now = arrangement[i];
        if(before == ")" && now ==")"){
            left.pop();
            answer+=1;
            continue;
        }
        if(arrangement[i] == '(')
            left.push(arrangement[i]);
        else{
            cout << left.top();
            left.pop();
            answer+=left.size();
        }
        
    }
    return answer;
}