Refactor to remove dependency on pre-Swift 4.

The code used to depend on pre-Swift 4's optional operators, which have since been replaced. Now, the one possible case for comparing a potential `nil` maximum value has been handled.

Author: SpacyRicochet

Bucket Sort/BucketSort.swift

@@ -20,31 +20,6 @@
 //
 //
 
-import Foundation
-// FIXME: comparison operators with optionals were removed from the Swift Standard Libary.
-// Consider refactoring the code to use the non-optional operators.
-fileprivate func < <T: Comparable>(lhs: T?, rhs: T?) -> Bool {
-  switch (lhs, rhs) {
-  case let (l?, r?):
-    return l < r
-  case (nil, _?):
-    return true
-  default:
-    return false
-  }
-}
-
-// FIXME: comparison operators with optionals were removed from the Swift Standard Libary.
-// Consider refactoring the code to use the non-optional operators.
-fileprivate func >= <T: Comparable>(lhs: T?, rhs: T?) -> Bool {
-  switch (lhs, rhs) {
-  case let (l?, r?):
-    return l >= r
-  default:
-    return !(lhs < rhs)
-  }
-}
-
 //////////////////////////////////////
 // MARK: Main algorithm
 //////////////////////////////////////
@@ -87,7 +62,11 @@ private func enoughSpaceInBuckets<T>(_ buckets: [Bucket<T>], elements: [T]) -> B
     let maximumValue = elements.max()?.toInt()
     let totalCapacity = buckets.count * (buckets.first?.capacity)!
 
-    return totalCapacity >= maximumValue
+    guard let max = maximumValue else {
+        return false
+    }
+    
+    return totalCapacity >= max
 }
 
 //////////////////////////////////////