Leetcode-67. Add Binary

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前言：为了后续的实习面试，开始疯狂刷题，非常欢迎志同道合的朋友一起交流。因为时间比较紧张，目前的规划是先过一遍，写出能想到的最优算法，第二遍再考虑最优或者较优的方法。如有错误欢迎指正。博主首发CSDN，mcf171专栏。

博客链接：mcf171的博客

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

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

这个题目没啥好说的。。Your runtime beats 37.16% of java submissions.

public class Solution {    public String addBinary(String a, String b) {        StringBuffer sb = new StringBuffer("");int carryNumber = 0;int i = a.length() - 1,j = b.length() - 1;while(i >= 0 && j >= 0){int sum = (a.charAt(i) - '0') + (b.charAt(j) - '0') + carryNumber;carryNumber = sum / 2;sb.insert(0,sum%2);i --; j --;}while( i >= 0){int sum = (a.charAt(i) - '0') + carryNumber;carryNumber = sum/2;sb.insert(0,sum%2);i--;}while( j >=0 ){int sum = (b.charAt(j) - '0') + carryNumber;carryNumber = sum/2;sb.insert(0,sum%2);j--;}if( carryNumber !=0 ) sb.insert(0,1);return sb.toString();    }}

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