[leetcode] add-binary

 1 /*
 2 * 字符转化为整型： int a = ‘1‘ - ‘0‘;
 3 * 整型转化为字符： char a = String.valueOf(‘1‘).charAt(0);
 4 * */
 5 
 6 public class Solution {
 7     public String addBinary(String a, String b) {
 8         int lengthMax = Math.max(a.length(), b.length());
 9         StringBuilder sb = new StringBuilder();
10         int carry = 0;
11         int sum = 0;
12         for (int i = 0; i < lengthMax || carry != 0; i++) {
13             int an = 0, bn = 0;
14             if (a.length() - 1 - i >= 0) {
15                 an = a.charAt(a.length() - 1 - i) - ‘0‘;
16             }
17             if (b.length() - 1 - i >= 0) {
18                 bn = b.charAt(b.length() - 1 - i) - ‘0‘;
19             }
20             sum = an + bn + carry;
21             sb.append(sum % 2);
22             carry = sum / 2;
23         }
24         return sb.reverse().toString();
25     }
26 
27     public static void main(String args[]) {
28         Solution solution = new Solution();
29         String s = solution.addBinary("0", "0");
30         System.out.println("number: " + s.length());
31         System.out.println(s.charAt(0));
32     }
33 }