1

#include <bits/stdc++.h>
using namespace std;
// 返回 x 的因子和
int f(int x)
{
    if (x <= 1)
        return 0;
    int res = 1;
    for (int i = 2; i <= x - 1; i++)
        if (x % i == 0)
            res += i;
    return res;
}
int main()
{
    for (int a = 1;; a++)
    {
        int b = f(a);
        if (a == f(b) && a != b)
        {
            cout << a << " " << b << "\n";
            break;
        }
    }
    return 0;
}

2

#include <bits/stdc++.h>
using namespace std;
//返回 x 的因子和
int f(int x)
{
    if (x <= 1)
        return 0;
    int res = 1;
    for (int i = 2; i * i <= x; i++)
        if (x % i == 0)
        {
            int j = x / i; //找到对应的另一个因子
            res += i;
            if (j != i)
                res += j;
        }
    return res;
}
int main()
{
    for (int a = 1;; a++)
    {
        int b = f(a);
        if (a == f(b) && a != b)
        {
            cout << a << " " << b << "\n";
            break;
        }
    }
    return 0;
}