Why my code is wrong? Help me please!!


import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int n, total = 0, soma = 0, diferenca = 100001, pilha2 = 0;
        int weights[] = new int[20];
        n = scan.nextInt();
        if (n == 1) {
            System.out.println(scan.next());
            return;
        }
        if (n == 2) {
            System.out.println(Math.abs(scan.nextInt() - scan.nextInt()));
            return;
        }
        for (int i = 0; i < n; i++) {
            weights[i] = scan.nextInt();
            total += weights[i];
        }
        for (int i = 0; i < n; i++) {
            soma = weights[i];
            for (int j = 0; j < n; j++) {
                pilha2 = 0;
                if (i != j) {
                    soma += weights[j];
                    pilha2 = total - soma;
                    if (diferenca > (Math.abs(pilha2 - soma))) {
                        diferenca = (Math.abs(pilha2 - soma));
                    }
                }
            }
        }
        System.out.println(diferenca);
    }

}

Use bitmasks, greedy algorithm is wrong