/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		System.out.print(addBinary("11", "1"));
	}
 
	public static String addBinary(String a, String b) {
        String ans="";
        int i=a.length()-1;
        int j=b.length()-1;
        int carry=0;
        while(i>=0 || j>=0 || carry==1){
            int add=carry;
            if(i>=0) add+=a.charAt(i)-'0';
            if(j>=0) add+=b.charAt(j)-'0';
            ans="" + (add%2) + ans;
            carry=add/2; 
            i--;
            j--;
        }
 
        System.out.print("ans=" +  ans);
        return ans;    
    }
}

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