Add Binary LeetCode Java

描述
Given two binary strings, return their sum (also a binary string).
For example,

a = "11"

b = "1"

Return ”100”

分析

无

代码

 1 public class AddBinary {
 2 
 3     public static void main(String[] args) {
 4         // TODO Auto-generated method stub
 5         String str1="111";
 6         String str2="1";
 7         System.out.println(addBinary (str1,str2));
 8 }
 9     public static String addBinary(String str1,String str2) {
10         if(str1==""||str2=="") return null;
11 //        int a1=Integer.parseInt(str1,2);
12 //        int a2=Integer.parseInt(str2,2);
13         
14         char[] ch1=str1.toCharArray();
15         char[] ch2=str2.toCharArray();
16         int a1=0,a2=0;
17         for(int i=0;i<ch1.length;i++) {
18             a1+=Math.pow(2, i)*(str1.charAt(ch1.length-1-i)-'0');
19         }
20         
21         for(int i=0;i<ch2.length;i++) {
22             a2+=Math.pow(2, i)*(str2.charAt(ch2.length-1-i)-'0');
23         }
24         int num=a1+a2;
25         String result=Integer.toBinaryString(num);
26         return result;
27    }
28     
29 }