UVA 10167 Birthday Cake

#include<stdio.h>
int main()
{
    int n, i, j, k;
    int x[1000], y[1000];
    while (~scanf("%d", &n))
    {
        if (n == 0) break;
        int sum1 = 0,sum2=0;
        int flag = 0;
        for (i = 0; i < 2 * n; i++) scanf("%d%d", &x[i], &y[i]);
        for (i = -500; i <= 500; i++)
        {
            sum1 = 0; sum2 = 0;
            for (j = -500; j <= 500; j++)
            {
                sum1 = 0; sum2 = 0;
                for (k = 0; k < 2 * n; k++)
                {
                    if (i*x[k] + j*y[k]>0) sum1++;
                    if (i*x[k] + j*y[k] < 0) sum2++;
                }
                if (sum1==sum2&&sum1==n) { flag = 1; break; }
            }
            if (flag == 1) break;
        }
        printf("%d %d\n", i, j);
    }
    return 0;
}