AddBinary.java

package LeetcodePractice;
public class AddBinary {
    public static String addBinary(String a, String b) {
        StringBuilder result = new StringBuilder();
        int i = a.length() - 1;
        int j = b.length() - 1;
        int carry = 0;

        while (i >= 0 || j >= 0 || carry > 0) {
            int sum = carry;

            if (i >= 0) sum += a.charAt(i--) - '0';
            if (j >= 0) sum += b.charAt(j--) - '0'; 

            result.append(sum % 2); 
            carry = sum / 2;
        }

        return result.reverse().toString(); 
    }

   
    public static void main(String[] args) {

        System.out.println(addBinary("11", "1")); 
        System.out.println(addBinary("1010", "1011"));
    }
    
}