Merge pull request kodecocodes#205 from raywenderlich/BinarySearchTreeSwift3

Binary search tree swift3

Author: kelvinlauKL

Binary Search Tree/Solution 1/BinarySearchTree.playground/Contents.swift

@@ -1,21 +1,21 @@
 //: Playground - noun: a place where people can play
 
 let tree = BinarySearchTree<Int>(value: 7)
-tree.insert(2)
-tree.insert(5)
-tree.insert(10)
-tree.insert(9)
-tree.insert(1)
+tree.insert(value: 2)
+tree.insert(value: 5)
+tree.insert(value: 10)
+tree.insert(value: 9)
+tree.insert(value: 1)
 
 tree
 tree.debugDescription
 
 let tree2 = BinarySearchTree<Int>(array: [7, 2, 5, 10, 9, 1])
 
-tree.search(5)
-tree.search(2)
-tree.search(7)
-tree.search(6)
+tree.search(value: 5)
+tree.search(value: 2)
+tree.search(value: 7)
+tree.search(value: 6)
 
 tree.traverseInOrder { value in print(value) }
 
@@ -24,7 +24,7 @@ tree.toArray()
 tree.minimum()
 tree.maximum()
 
-if let node2 = tree.search(2) {
+if let node2 = tree.search(value: 2) {
   node2.remove()
   node2
   print(tree)
@@ -34,25 +34,25 @@ tree.height()
 tree.predecessor()
 tree.successor()
 
-if let node10 = tree.search(10) {
+if let node10 = tree.search(value: 10) {
   node10.depth()        // 1
   node10.height()       // 1
   node10.predecessor()
   node10.successor()    // nil
 }
 
-if let node9 = tree.search(9) {
+if let node9 = tree.search(value: 9) {
   node9.depth()        // 2
   node9.height()       // 0
   node9.predecessor()
   node9.successor()
 }
 
-if let node1 = tree.search(1) {
+if let node1 = tree.search(value: 1) {
   // This makes it an invalid binary search tree because 100 is greater
   // than the root, 7, and so must be in the right branch not in the left.
   tree.isBST(minValue: Int.min, maxValue: Int.max)  // true
-  node1.insert(100)
-  tree.search(100)                                  // nil
+  node1.insert(value: 100)
+  tree.search(value: 100)                                  // nil
   tree.isBST(minValue: Int.min, maxValue: Int.max)  // false
 }

Binary Search Tree/Solution 1/BinarySearchTree.playground/Sources/BinarySearchTree.swift

@@ -10,10 +10,10 @@
   you should insert new values in randomized order, not in sorted order.
 */
 public class BinarySearchTree<T: Comparable> {
-  private(set) public var value: T
-  private(set) public var parent: BinarySearchTree?
-  private(set) public var left: BinarySearchTree?
-  private(set) public var right: BinarySearchTree?
+  fileprivate(set) public var value: T
+  fileprivate(set) public var parent: BinarySearchTree?
+  fileprivate(set) public var left: BinarySearchTree?
+  fileprivate(set) public var right: BinarySearchTree?
 
   public init(value: T) {
     self.value = value
@@ -22,8 +22,8 @@ public class BinarySearchTree<T: Comparable> {
   public convenience init(array: [T]) {
     precondition(array.count > 0)
     self.init(value: array.first!)
-    for v in array.dropFirst() {
-      insert(v, parent: self)
+    for v in array.dropFirst() { 
+      insert(value: v, parent: self)
     }
   }
 
@@ -74,20 +74,20 @@ extension BinarySearchTree {
     Performance: runs in O(h) time, where h is the height of the tree.
   */
   public func insert(value: T) {
-    insert(value, parent: self)
+    insert(value: value, parent: self)
   }
 
-  private func insert(value: T, parent: BinarySearchTree) {
+  fileprivate func insert(value: T, parent: BinarySearchTree) {
     if value < self.value {
       if let left = left {
-        left.insert(value, parent: left)
+        left.insert(value: value, parent: left)
       } else {
         left = BinarySearchTree(value: value)
         left?.parent = parent
       }
     } else {
       if let right = right {
-        right.insert(value, parent: right)
+        right.insert(value: value, parent: right)
       } else {
         right = BinarySearchTree(value: value)
         right?.parent = parent
@@ -108,7 +108,7 @@ extension BinarySearchTree {
 
     Performance: runs in O(h) time, where h is the height of the tree.
   */
-  public func remove() -> BinarySearchTree? {
+  @discardableResult public func remove() -> BinarySearchTree? {
     let replacement: BinarySearchTree?
 
     if let left = left {
@@ -126,7 +126,7 @@ extension BinarySearchTree {
       replacement = nil
     }
 
-    reconnectParentToNode(replacement)
+    reconnectParentTo(node: replacement)
 
     // The current node is no longer part of the tree, so clean it up.
     parent = nil
@@ -136,7 +136,7 @@ extension BinarySearchTree {
     return replacement
   }
 
-  private func removeNodeWithTwoChildren(left: BinarySearchTree, _ right: BinarySearchTree) -> BinarySearchTree {
+  private func removeNodeWithTwoChildren(_ left: BinarySearchTree, _ right: BinarySearchTree) -> BinarySearchTree {
     // This node has two children. It must be replaced by the smallest
     // child that is larger than this node's value, which is the leftmost
     // descendent of the right child.
@@ -164,7 +164,7 @@ extension BinarySearchTree {
     return successor
   }
 
-  private func reconnectParentToNode(node: BinarySearchTree?) {
+  private func reconnectParentTo(node: BinarySearchTree?) {
     if let parent = parent {
       if isLeftChild {
         parent.left = node
@@ -211,7 +211,7 @@ extension BinarySearchTree {
   */
 
   public func contains(value: T) -> Bool {
-    return search(value) != nil
+    return search(value: value) != nil
   }
 
   /*
@@ -298,32 +298,32 @@ extension BinarySearchTree {
 // MARK: - Traversal
 
 extension BinarySearchTree {
-  public func traverseInOrder(@noescape process: T -> Void) {
-    left?.traverseInOrder(process)
+  public func traverseInOrder(process: (T) -> Void) {
+    left?.traverseInOrder(process: process)
     process(value)
-    right?.traverseInOrder(process)
+    right?.traverseInOrder(process: process)
   }
 
-  public func traversePreOrder(@noescape process: T -> Void) {
+  public func traversePreOrder(process: (T) -> Void) {
     process(value)
-    left?.traversePreOrder(process)
-    right?.traversePreOrder(process)
+    left?.traversePreOrder(process: process)
+    right?.traversePreOrder(process: process)
   }
 
-  public func traversePostOrder(@noescape process: T -> Void) {
-    left?.traversePostOrder(process)
-    right?.traversePostOrder(process)
+  public func traversePostOrder(process: (T) -> Void) {
+    left?.traversePostOrder(process: process)
+    right?.traversePostOrder(process: process)
     process(value)
   }
 
   /*
     Performs an in-order traversal and collects the results in an array.
   */
-  public func map(@noescape formula: T -> T) -> [T] {
+  public func map(formula: (T) -> T) -> [T] {
     var a = [T]()
-    if let left = left { a += left.map(formula) }
+    if let left = left { a += left.map(formula: formula) }
     a.append(formula(value))
-    if let right = right { a += right.map(formula) }
+    if let right = right { a += right.map(formula: formula) }
     return a
   }
 }
@@ -332,7 +332,7 @@ extension BinarySearchTree {
   Is this binary tree a valid binary search tree?
 */
 extension BinarySearchTree {
-  public func isBST(minValue minValue: T, maxValue: T) -> Bool {
+  public func isBST(minValue: T, maxValue: T) -> Bool {
     if value < minValue || value > maxValue { return false }
     let leftBST = left?.isBST(minValue: minValue, maxValue: value) ?? true
     let rightBST = right?.isBST(minValue: value, maxValue: maxValue) ?? true

Binary Search Tree/Solution 2/BinarySearchTree.playground/Contents.swift

@@ -2,13 +2,15 @@
 
 // Each time you insert something, you get back a completely new tree.
 var tree = BinarySearchTree.Leaf(7)
-tree = tree.insert(2)
-tree = tree.insert(5)
-tree = tree.insert(10)
-tree = tree.insert(9)
-tree = tree.insert(1)
+tree = tree.insert(newValue: 2)
+tree = tree.insert(newValue: 5)
+tree = tree.insert(newValue: 10)
+tree = tree.insert(newValue: 9)
+tree = tree.insert(newValue: 1)
 print(tree)
 
-tree.search(10)
-tree.search(1)
-tree.search(11)
+tree.search(x: 10)
+tree.search(x: 1)
+tree.search(x: 11)
+
+

Binary Search Tree/Solution 2/BinarySearchTree.playground/Sources/BinarySearchTree.swift

@@ -44,9 +44,9 @@ public enum BinarySearchTree<T: Comparable> {
 
     case .Node(let left, let value, let right):
       if newValue < value {
-        return .Node(left.insert(newValue), value, right)
+        return .Node(left.insert(newValue: newValue), value, right)
       } else {
-        return .Node(left, value, right.insert(newValue))
+        return .Node(left, value, right.insert(newValue: newValue))
       }
     }
   }
@@ -63,17 +63,17 @@ public enum BinarySearchTree<T: Comparable> {
       return (x == y) ? self : nil
     case let .Node(left, y, right):
       if x < y {
-        return left.search(x)
+        return left.search(x: x)
       } else if y < x {
-        return right.search(x)
+        return right.search(x: x)
       } else {
         return self
       }
     }
   }
 
   public func contains(x: T) -> Bool {
-    return search(x) != nil
+    return search(x: x) != nil
   }
 
   /*