BINARY SUBTRACTION COA

import java.util.*;

public class BinarySubtraction {
    static int flag = 0;

    /**
     * @param args
     */
    static int[] decimalToBinary(int a, int length) {

        int binary[] = new int[length];
        int i = binary.length - 1;
        if (a < 0) {
            a = (int) (Math.pow(2, length)) - Math.abs(a);
        }
        while (a != 0) {
            binary[i] = a % 2;
            a /= 2;
            i--;
        }

        return binary;
    }

    static int[] add(int a[], int b[]) {
        int[] result = new int[a.length];
        for (int i = a.length - 1; i >= 0; i--) {
            result[i] = (a[i] + b[i] + flag) % 2;
            flag = (a[i] + b[i] + flag) / 2;
        }

        return result;

    }

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner sc = new Scanner(System.in);
        System.out.println("Enter the first number : ");
        int x = sc.nextInt();
        System.out.println("Enter the second number : ");
        int y = sc.nextInt();
        int greater = Math.abs(x) > Math.abs(y) ? Math.abs(x) : Math.abs(y);
        int length = (int) (Math.log(Math.abs(greater)) / Math.log(2)) + 2;
        int a[] = decimalToBinary(x, length);
        int b[] = decimalToBinary(y, length);
        System.out.println("a : " + Arrays.toString(a) + "  \nb : "
                + Arrays.toString(b));
        System.out.println("RESULT : " + Arrays.toString(add(a, b)));
    }

}
/*
 * Enter the first number : 5 Enter the second number : -9
 * a : [0, 0, 1, 0, 1]
 * b : [1, 0, 1, 1, 1]
 * RESULT : [1, 1, 1, 0, 0]
 */