Leetcode-67-Add Binary 二进制数相加

Add Binary

package leetcode;

public class mm {
      public static String addBinary(String a, String b) {

            StringBuilder str = new StringBuilder();
            //二进制数相加，应从最右边开始！
            int i=a.length();
            int j=b.length();
            int sum=0;
            int jinwei = 0;
            while(i>0||j>0){
                sum=jinwei;
                if(i>0)
                    sum+=a.charAt(--i)-'0';
                if(j>0)
                    sum+=b.charAt(--j)-'0';
                jinwei=sum/2;
                str.append(sum%2);
            }
            if(jinwei!=0)
                str.append(jinwei);
            return str.reverse().toString();

        }
     public static void main(String[] args) {
        String a="1010";
        String b="1011";
        System.out.println(addBinary(a,b));
    }
}