Merge pull request #227 from hellomrsun/master

Add Add Binary C#

Author: jinshendan

July-LeetCoding-Challenge/19-Add-Binary/Add-Binary.cs

@@ -0,0 +1,18 @@
+public class Solution {
+    public string AddBinary(string a, string b)
+    {
+        var sb = new StringBuilder();
+        int i = a.Length-1, j = b.Length-1, carry = 0;
+        while(i >=0 || j >= 0){
+            int sum = carry;
+            if(i >= 0) sum += a[i--] - '0';
+            if(j >= 0) sum += b[j--] - '0';
+            sb.Append(sum % 2);
+            carry = sum /2;
+        }
+        if(carry != 0) sb.Append(carry);
+        var arr = sb.ToString().ToCharArray();
+        Array.Reverse(arr);
+        return new String(arr);
+    }
+}

README.md

@@ -25,7 +25,7 @@ Solutions in various programming languages are provided. Enjoy it.
 16. [Pow(x,n)](https://github.com/AlgoStudyGroup/Leetcode/tree/master/July-LeetCoding-Challenge/16-Pow(x,n)): Recursion
 17. [Top K Frequent Elements](https://github.com/AlgoStudyGroup/Leetcode/tree/master/July-LeetCoding-Challenge/17-Top-K-Frequent-Elements): Bucket
 18. [Course Schedule II](https://github.com/AlgoStudyGroup/Leetcode/tree/master/July-LeetCoding-Challenge/18-Course-Schedule-II): BFS
-
+19. [Add Binary](https://github.com/AlgoStudyGroup/Leetcode/tree/master/July-LeetCoding-Challenge/19-Add-Binary)
 
 ## June LeetCoding Challenge
 Click [here](https://leetcode.com/explore/challenge/card/june-leetcoding-challenge/) for problem descriptions.