[3986번] ESEJ(Nice Word) - Stack [C++] ☆

https://www.acmicpc.net/problem/3986

#include <stack>
#include <stdio.h>
#include <iostream>
#include <string>
 
using namespace std;
 
int main() {
    int N;
    unsigned long long count = 0;
    cin >> N;
    for (int i = 0; i < N; i++) {
        stack<char> stack1;
        string input;
        cin >> input;
        for (int i = 0; i < input.size(); i++) {
            // method 1
            if (!stack1.empty() && input[i] == stack1.top())
                stack1.pop();
            else
                stack1.push(input[i]);
            /* method 2
            if (stack1.empty())
                stack1.push(input[i]);
            else {
                if (input[i] == stack1.top())
                    stack1.pop();
                else
                    stack1.push(input[i]);
            }
            */
        }
        if (stack1.empty())
            count++;
    }
    cout << count;
    return 0;
}