Updated Knuth-Morris-Pratt to Swift 4.2

Author: karolms

Knuth-Morris-Pratt/KnuthMorrisPratt.playground/Contents.swift

@@ -1,13 +1,8 @@
 //: Playground - noun: a place where people can play
 
-// last checked with Xcode 9.0b4
-#if swift(>=4.0)
-print("Hello, Swift4!")
-#endif
-
 func ZetaAlgorithm(ptnr: String) -> [Int]? {
 
-  let pattern = Array(ptnr.characters)
+  let pattern = Array(ptnr)
   let patternLength: Int = pattern.count
 
   guard patternLength > 0 else {
@@ -65,7 +60,7 @@ extension String {
 
   func indexesOf(ptnr: String) -> [Int]? {
 
-    let text = Array(self.characters)
+    let text = Array(self)
     let pattern = Array(ptnr.characters)
 
     let textLength: Int = text.count