UVa 10177 - (2/3/4)-D Sqr/Rects/Cubes/Boxes?

对于每个n所对应的6个数，有以下规律：

a1=∑i^2(i=1…n);

a2=(∑i(i=1…n))^2-a1;

a3=∑i^3(i=1…n);

a4=(∑i(i=1…n))^3-a3;

a5=∑i^4(i=1…n);

a6=(∑i(i=1…n))^4-a5;

#include <iostream>

using namespace std;

int main()
{
    int n;
    while(cin>>n)
    {
        long long a1=0,a2=0,a3=0,t=0;
        for(long long i=1;i<=n;i++)
        {
            a1+=i*i;
            a2+=i*i*i;
            a3+=i*i*i*i;
            t+=i;
        }
        cout<<a1<<" "<<(t*t)-a1<<" "<<a2<<" "<<(t*t*t)-a2
        <<" "<<a3<<" "<<(t*t*t*t)-a3<<endl;
    }
    return 0;
}