67. Add Binary

67. Add Binary

• 题目描述：Given two binary strings, return their sum (also a binary string).

  For example,
  a = "11"
  b = "1"
  Return "100".

• 题目大意：进行二进制加减

• 思路：直接运用二进制加减规则进行加减即可

• 代码

  package String;/*** @Author OovEver* @Date 2017/12/6 14:40*/public class LeetCode67 {  public String addBinary(String a, String b) {      StringBuilder stringBuilder = new StringBuilder();      int i = a.length() - 1;      int j = b.length() - 1;      int sum = 0;      int carry = 0;      while (i >= 0 || j >= 0) {          sum = carry;          if (i >= 0) {              sum += a.charAt(i--) - '0';          }          if (j >= 0) {              sum += b.charAt(j--) - '0';          }          stringBuilder.append(sum % 2);          carry = sum / 2;      }      if (carry != 0) {          stringBuilder.append(carry);      }      return stringBuilder.reverse().toString();  }}