Merge pull request #1615 from a93a/67

Create 67-Add-Binary.kt

Author: Ahmad-A0

kotlin/67-Add-Binary.kt

@@ -0,0 +1,15 @@
+class Solution {
+    fun addBinary(a: String, b: String): String {
+        var rsum = ""; var carry = 0; var aL = a.length-1; var bL = b.length-1
+        while(aL >= 0 || bL >= 0){
+            var aBit = if(aL >= 0) a[aL--] else '0'
+            var bBit = if(bL >= 0) b[bL--] else '0'
+            val sum = aBit.toString().toInt() + bBit.toString().toInt() + carry
+            carry = sum / 2
+            rsum = (sum % 2).toString() + rsum
+        }
+        if(carry > 0)
+            rsum = '1' + rsum
+        return rsum
+    }
+}