C++ 알고리즘 - 백준 1541 잃어버린 괄호

https://www.acmicpc.net/problem/1541

 

#include <bits/stdc++.h>
#define endl "\n"

using namespace std;

int main(void) {
	/************** C++ Init **************/
	ios::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);
	/************** C++ Init **************/


	string str;
	string num;
	int sum = 0;
	bool minus = false;

	cin >> str;

	for (int i = 0; i <= str.size(); i++) {
		if (str[i] == '-' || str[i] == '+' || i == str.size()) {
			if (minus) {
				sum -= stoi(num);
				num = "";
			}

			else {
				sum += stoi(num);
				num = "";
			}
		}

		else {
			num += str[i];
		}
		
		if (str[i] == '-') minus = true;
	}

	cout << sum;
}