Gold Coins

http://poj.org/problem?id=2000

#include<stdio.h>
const int N=10010;
int main()
{
    int coin[N];
    long long  n,i = 1,j,k;
    j = 1;
    k = 0;
    while (i < 10010)
    {
        if (k < j)
        {
            coin[i++] = j;
            k++;
        }
        if (k >= j)
        {
            k = 0;
            j++;
        }

    }
    while(~scanf("%lld",&n)&&n)
    {
        long long scoin = 0;
        for (i = 1; i <= n; i ++)
            scoin += coin[i];
        printf("%lld %lld
",n,scoin);
    }
    return 0;
}