Merge pull request #747 from JulioBBL/insertion-sort

Insertion sort improvements

Author: kelvinlauKL

Insertion Sort/InsertionSort.playground/Contents.swift

@@ -5,20 +5,47 @@
 print("Hello, Swift 4!")
 #endif
 
+/// Performs the Insertion sort algorithm to a given array
+///
+/// - Parameters:
+///   - array: the array of elements to be sorted
+///   - isOrderedBefore: returns true if the elements provided are in the corect order
+/// - Returns: a sorted array containing the same elements
 func insertionSort<T>(_ array: [T], _ isOrderedBefore: (T, T) -> Bool) -> [T] {
-  var a = array
-  for x in 1..<a.count {
-    var y = x
-    let temp = a[y]
-    while y > 0 && isOrderedBefore(temp, a[y - 1]) {
-      a[y] = a[y - 1]
-      y -= 1
+    guard array.count > 1 else { return array }
+    
+    var a = array
+    for x in 1..<a.count {
+        var y = x
+        let temp = a[y]
+        while y > 0 && isOrderedBefore(temp, a[y - 1]) {
+            a[y] = a[y - 1]
+            y -= 1
+        }
+        a[y] = temp
     }
-    a[y] = temp
-  }
-  return a
+    return a
+}
+
+/// Performs the Insertion sort algorithm to a given array
+///
+/// - Parameter array: the array to be sorted, conatining elements that conform to the Comparable protocol
+/// - Returns: a sorted array containing the same elements
+func insertionSort<T: Comparable>(_ array: [T]) -> [T] {
+    var a = array
+    for x in 1..<a.count {
+        var y = x
+        let temp = a[y]
+        while y > 0 && temp < a[y - 1] {
+            a[y] = a[y - 1]
+            y -= 1
+        }
+        a[y] = temp
+    }
+    return a
 }
 
 let list = [ 10, -1, 3, 9, 2, 27, 8, 5, 1, 3, 0, 26 ]
-insertionSort(list, <)
-insertionSort(list, >)
+print(insertionSort(list))
+print(insertionSort(list, <))
+print(insertionSort(list, >))

Insertion Sort/InsertionSort.playground/contents.xcplayground

@@ -1,4 +1,4 @@
 <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
-<playground version='5.0' target-platform='osx'>
+<playground version='5.0' target-platform='osx' executeOnSourceChanges='false'>
     <timeline fileName='timeline.xctimeline'/>
 </playground>

Insertion Sort/InsertionSort.playground/playground.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>IDEDidComputeMac32BitWarning</key>
+	<true/>
+</dict>
+</plist>

Insertion Sort/InsertionSort.swift

@@ -1,3 +1,9 @@
+/// Performs the Insertion sort algorithm to a given array
+///
+/// - Parameters:
+///   - array: the array of elements to be sorted
+///   - isOrderedBefore: returns true if the elements provided are in the corect order
+/// - Returns: a sorted array containing the same elements
 func insertionSort<T>(_ array: [T], _ isOrderedBefore: (T, T) -> Bool) -> [T] {
   guard array.count > 1 else { return array }
 
@@ -13,3 +19,23 @@ func insertionSort<T>(_ array: [T], _ isOrderedBefore: (T, T) -> Bool) -> [T] {
   }
   return a
 }
+
+/// Performs the Insertion sort algorithm to a given array
+///
+/// - Parameter array: the array to be sorted, conatining elements that conform to the Comparable protocol
+/// - Returns: a sorted array containing the same elements
+func insertionSort<T: Comparable>(_ array: [T]) -> [T] {
+    guard array.count > 1 else { return array }
+
+    var a = array
+    for x in 1..<a.count {
+        var y = x
+        let temp = a[y]
+        while y > 0 && temp < a[y - 1] {
+            a[y] = a[y - 1]
+            y -= 1
+        }
+        a[y] = temp
+    }
+    return a
+}

Insertion Sort/Tests/Tests.xcodeproj/project.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>IDEDidComputeMac32BitWarning</key>
+	<true/>
+</dict>
+</plist>