my program variation:

#include <stdio.h>
#include <math.h>

int main()
{
    int nrstones, i, min, w1, w2;
    int *weights;

    scanf("%d", &nrstones);
    weights = new int[nrstones];
    for(i = 0; i < nrstones; i++)
    {
        scanf("%d", &weights[i]);
    }

    min = weights[0];

    int perm = 1 << nrstones;

    for(i = 0; i < perm; i++)
    {
        w1 = 0;
        w2 = 0;
        int j;
        for(j = 0; j < nrstones; j++)
        {
            if((i >> j) % 2 == 0)
                w1 += weights[j];
            else
                w2 += weights[j];
        }

        if(min > abs((double)w1 - w2))
        {
            min = abs((double)w1 - w2);
            if(min == 0)
            {
                printf("%d", min);
                return 0;
            }
        }
    }
    printf("%d", min);
    return 0;
}