Updated radixSort argument to swift3 syntax.

Author: taiheng

Radix Sort/radixSort.swift

@@ -5,43 +5,42 @@
 */
 
 
-func radixSort(inout arr: [Int] ) {
-
-
+// NOTE: This implementation does not handle negative numbers
+func radixSort(_ array: inout [Int] ) {
   let radix = 10  //Here we define our radix to be 10
   var done = false
   var index: Int
   var digit = 1  //Which digit are we on?
-
-
+  
+  
   while !done {  //While our  sorting is not completed
     done = true  //Assume it is done for now
-
+    
     var buckets: [[Int]] = []  //Our sorting subroutine is bucket sort, so let us predefine our buckets
-
+    
     for _ in 1...radix {
       buckets.append([])
     }
-
-
-    for number in arr {
+    
+    
+    for number in array {
       index = number / digit  //Which bucket will we access?
       buckets[index % radix].append(number)
       if done && index > 0 {  //If we arent done, continue to finish, otherwise we are done
         done = false
       }
     }
-
+    
     var i = 0
-
+    
     for j in 0..<radix {
       let bucket = buckets[j]
       for number in bucket {
-        arr[i] = number
+        array[i] = number
         i += 1
       }
     }
-
+    
     digit *= radix  //Move to the next digit
   }
 }