f(n)=(n*n+n)/2

g(n)=(n*n*n+3*n*n+2*n)/6

記得變數開大一點(long long int)

#include<iostream>

using namespace std;

int main()

{

    long long int n, f, g;

    while(cin>>n)

    {

        f = (n*n+n)/2;

        g = (n*n*n+3*n*n+2*n)/6;

        cout << f << " " << g << endl;

    }

}