Updated random number generation to Swift 4.2

Author: iillx

Set Cover (Unweighted)/SetCover.playground/Contents.swift

@@ -1,10 +1,5 @@
 // SetCover
 
-// last checked with Xcode 9.0b4
-#if swift(>=4.0)
-print("Hello, Swift 4!")
-#endif
-
 let universe1 = Set(1...7)
 let array1 = randomArrayOfSets(covering: universe1)
 let cover1 = universe1.cover(within: array1)
@@ -36,3 +31,5 @@ let emptySet = Set<Int>()
 let coverTest1 = emptySet.cover(within: array1)
 let coverTest2 = universe1.cover(within: Array<Set<Int>>())
 let coverTest3 = emptySet.cover(within: Array<Set<Int>>())
+
+

Set Cover (Unweighted)/SetCover.playground/Sources/RandomArrayOfSets.swift

@@ -14,10 +14,10 @@ public func randomArrayOfSets<T>(covering universe: Set<T>,
 
   while true {
     var generatedSet = Set<T>()
-    let targetSetSize = Int(arc4random_uniform(UInt32(maxSetSize)) + 1)
+    let targetSetSize = Int.random(in: 0...maxSetSize) + 1
 
     while true {
-      let randomUniverseIndex = Int(arc4random_uniform(UInt32(universe.count)))
+      let randomUniverseIndex = Int.random(in: 0...universe.count)
       for (setIndex, value) in universe.enumerated() {
         if setIndex == randomUniverseIndex {
           generatedSet.insert(value)