Data commit

Task/Tree-traversal/Swift/tree-traversal.swift

@@ -0,0 +1,86 @@
+class TreeNode<T> {
+    let value: T
+    let left: TreeNode?
+    let right: TreeNode?
+
+    init(value: T, left: TreeNode? = nil, right: TreeNode? = nil) {
+        self.value = value
+        self.left = left
+        self.right = right
+    }
+
+    func preOrder(function: (T) -> Void) {
+        function(value)
+        if left != nil {
+            left!.preOrder(function: function)
+        }
+        if right != nil {
+            right!.preOrder(function: function)
+        }
+    }
+
+    func inOrder(function: (T) -> Void) {
+        if left != nil {
+            left!.inOrder(function: function)
+        }
+        function(value)
+        if right != nil {
+            right!.inOrder(function: function)
+        }
+    }
+
+    func postOrder(function: (T) -> Void) {
+        if left != nil {
+            left!.postOrder(function: function)
+        }
+        if right != nil {
+            right!.postOrder(function: function)
+        }
+        function(value)
+    }
+
+    func levelOrder(function: (T) -> Void) {
+        var queue: [TreeNode] = []
+        queue.append(self)
+        while queue.count > 0 {
+            let node = queue.removeFirst()
+            function(node.value)
+            if node.left != nil {
+                queue.append(node.left!)
+            }
+            if node.right != nil {
+                queue.append(node.right!)
+            }
+        }
+    }
+}
+
+typealias Node = TreeNode<Int>
+
+let n = Node(value: 1,
+             left: Node(value: 2,
+                        left: Node(value: 4,
+                                   left: Node(value: 7)),
+                        right: Node(value: 5)),
+             right: Node(value: 3,
+                         left: Node(value: 6,
+                                    left: Node(value: 8),
+                                    right: Node(value: 9))))
+
+let fn = { print($0, terminator: " ") }
+
+print("pre-order:   ", terminator: "")
+n.preOrder(function: fn)
+print()
+
+print("in-order:    ", terminator: "")
+n.inOrder(function: fn)
+print()
+
+print("post-order:  ", terminator: "")
+n.postOrder(function: fn)
+print()
+
+print("level-order: ", terminator: "")
+n.levelOrder(function: fn)
+print()