Subset Sums Counter

package demo;
// In a given set of numbers, find all subsets that are equal to 0;
public class HelloJava {
    public static void main(String[] args) {
        int[] numbers = {1, 0, -1, 2, 3, -2};
        int length = numbers.length;
        int sum = 0; // subset sum we look for
        int currentSum = 0;
        int counter = 0; // increment if subset found

        int combinations = (int) Math.pow(2, length) - 1;

        // go over all combinations from 00..1 => 11..1
        for(int i = 1; i < combinations; i++){
            String bin = Integer.toBinaryString(i);
            bin = padLeft(bin, '0', length);

            currentSum = 0;
            int digit = 0;
            // if char at bin is 1 get numbers[j]
            for(int j = 0; j < bin.length(); j++){
                digit = (bin.charAt(j) == '1') ? 1 : 0;
                if(digit == 1){
                    currentSum +=  numbers[j];
                }
            }

            // compare & increment if necessary
            if(currentSum == sum){
                counter++;
            }
        }

        System.out.println("Subset Sums found: " + counter);
    }

    public static String padLeft(String str, char symbol, int length){
        int padding = length - str.length();

        if(padding > 0){
            for(int i = 0; i < padding; i++){
                str = symbol + str;
            }
        }

        return str;
    }
}