Removes Swift 4.0 check.

Removes unused import.
Refactors an if statement into a guard to be more Swift-y.

Author: laurentaylormarshall

Slow Sort/SlowSort.playground/Contents.swift

@@ -1,8 +1,3 @@
-// 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)

Slow Sort/SlowSort.swift

@@ -6,12 +6,9 @@
 //
 //
 
-import Foundation
-
 public func slowsort(_ i: Int, _ j: Int, _ numberList: inout [Int]) {
-  if i>=j {
-    return
-  }
+  guard i<j else { return }
+    
   let m = (i+j)/2
   slowsort(i, m, &numberList)
   slowsort(m+1, j, &numberList)