Removes Swift 4.0 check.

Removes unused import.
Refactors an if statement into a guard to be more Swift-y.
Removes unnecessarily explicitly defining the function as public.

Author: laurentaylormarshall

Slow Sort/SlowSort.playground/Contents.swift

@@ -1,9 +1,4 @@
-// last checked with Xcode 9.0b4
-#if swift(>=4.0)
-print("Hello, Swift 4!")
-#endif
-
 var numberList = [1, 12, 9, 17, 13, 12]
 
-slowsort(0, numberList.count-1, &numberList)
+slowSort(0, numberList.count-1, &numberList)
 print(numberList)

Slow Sort/SlowSort.swift

@@ -6,12 +6,8 @@
 //
 //
 
-import Foundation
-
-public func slowsort(_ i: Int, _ j: Int, _ numberList: inout [Int]) {
-  if i>=j {
-    return
-  }
+func slowSort(_ i: Int, _ j: Int, _ numberList: inout [Int]) {
+  guard if i < j else { return }
   let m = (i+j)/2
   slowsort(i, m, &numberList)
   slowsort(m+1, j, &numberList)