题解 | #完全数计算#

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

int main() {
    int n;
    cin >> n;
    int ans = 0;
    while(n-- > 2){
        vector<int> vec;
        vec.push_back(1);
        for(int i = 2; i < sqrt(n); i++){
            if(n % i == 0){
                vec.push_back(i);
                vec.push_back(n / i);
            }
        }
        int x = sqrt(n);
        if(n % x == 0) vec.push_back(x);
        int sum = 0;
        for(int it : vec) sum += it;
        if(sum == n) ans++;
    }
    cout << ans << endl;
    return 0;
}