[백준] 9506번 약수들의 합

https://www.acmicpc.net/problem/9506

9506번: 약수들의 합

#include <iostream>
#include <set>
#include <cmath>
using namespace std;


int main() {
	while (true) {
		set<int> s;
		int n;
		cin >> n;
		if (n == -1) break;
		for (int i = 1; i <= sqrt(n); i++) {
			if (n % i == 0) {
				if(n / i != n) 
					s.insert(n / i);
				s.insert(i);
			}
		}
		int total = 0;
		for (set<int>::iterator iter = s.begin(); iter != s.end(); iter++) {
			total += (*iter);
		}
		int count = 0;
		if (total == n) {
			cout << n << " = ";
			for (set<int>::iterator iter = s.begin(); iter != s.end(); iter++) {
				cout << (*iter);
				if (count < s.size() - 1) {
					cout << " + ";
				}
				count++;
			}
			cout << '\n';
		}
		else {
			cout << n << " is NOT perfect.\n";
		}
	}
	return 0;
}