Data commit

Task/Tree-traversal/C-sharp/tree-traversal.cs

@@ -0,0 +1,72 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+class Node
+{
+    int Value;
+    Node Left;
+    Node Right;
+
+    Node(int value = default(int), Node left = default(Node), Node right = default(Node))
+    {
+        Value = value;
+        Left = left;
+        Right = right;
+    }
+
+    IEnumerable<int> Preorder()
+    {
+        yield return Value;
+        if (Left != null)
+            foreach (var value in Left.Preorder())
+                yield return value;
+        if (Right != null)
+            foreach (var value in Right.Preorder())
+                yield return value;
+    }
+
+    IEnumerable<int> Inorder()
+    {
+        if (Left != null)
+            foreach (var value in Left.Inorder())
+                yield return value;
+        yield return Value;
+        if (Right != null)
+            foreach (var value in Right.Inorder())
+                yield return value;
+    }
+
+    IEnumerable<int> Postorder()
+    {
+        if (Left != null)
+            foreach (var value in Left.Postorder())
+                yield return value;
+        if (Right != null)
+            foreach (var value in Right.Postorder())
+                yield return value;
+        yield return Value;
+    }
+
+    IEnumerable<int> LevelOrder()
+    {
+        var queue = new Queue<Node>();
+        queue.Enqueue(this);
+        while (queue.Any())
+        {
+            var node = queue.Dequeue();
+            yield return node.Value;
+            if (node.Left != null)
+                queue.Enqueue(node.Left);
+            if (node.Right != null)
+                queue.Enqueue(node.Right);
+        }
+    }
+
+    static void Main()
+    {
+        var tree = new Node(1, new Node(2, new Node(4, new Node(7)), new Node(5)), new Node(3, new Node(6, new Node(8), new Node(9))));
+        foreach (var traversal in new Func<IEnumerable<int>>[] { tree.Preorder, tree.Inorder, tree.Postorder, tree.LevelOrder })
+            Console.WriteLine("{0}:\t{1}", traversal.Method.Name, string.Join(" ", traversal()));
+    }
+}