Why WA on test1.
I think this is rigth.

#include <iostream>
#include <bitset>
using namespace std;

int main()
{
    int n,max = 1,summa, temp;
    int *w;
    cin >> n;
    w = new int[n];
    for(int i = 0; i < n; i++)
    {
        max *= 2;
        cin >> w[i];
    }
    max -= 2;
    bitset<20> a;
    temp = w[0];
    while(max >= 1)
    {
        a = max;
        summa = 0;
        for(int i = 0; i < n; i++)
        {
            if(a.at(i))
                summa += w[i];
            else
                summa -= w[i];
        }
        if(temp > summa && summa >= 0)
            temp = summa;
        max--;
    }
    cout << temp;
    return 0;
}