package leetcode.easy;

public class AddBinary {

	@org.junit.Test

	public void test() {

		String a1 = "11";

		String b1 = "1";

		String a2 = "1010";

		String b2 = "1011";

		System.out.println(addBinary(a1, b1));

		System.out.println(addBinary(a2, b2));

	}

	public String addBinary(String a, String b) {

		StringBuffer buffer = new StringBuffer();

		int sum = 0;

		int carry = 0;

		for (int i = a.length() - 1, j = b.length() - 1; i >= 0 || j >= 0; i--, j--) {

			sum = carry;

			if (i >= 0) {

				sum += a.charAt(i) - '0';

			}

			if (j >= 0) {

				sum += b.charAt(j) - '0';

			}

			buffer.append(sum % 2);

			carry = sum / 2;

		}

		if (carry != 0) {

			buffer.append(carry);

		}

		return buffer.reverse().toString();

	}

}