Add Level Order Traversal in Kotlin (#2757)

Tree_Levelorder_Traversal/Tree_Levelorder_Traversal.kt

@@ -0,0 +1,104 @@
+// Code for printing Level Order of Tree in Kotlin
+
+class Node
+{
+    //Structure of Binary tree node
+    int num;
+    Node left, right;
+    public Node(int num)
+    {
+        key = item;
+        left = right = null;
+    }
+}
+
+class BinaryTree
+{
+    Node root;
+    BinaryTree()
+    {
+        root = null;
+    }
+
+    //function to print level order traversal
+    fun printLevelOrder():void
+    {
+        int h = height(root);
+        int i;
+	// To Print nodes at each level
+        for (i = 1; i <= h; i++)
+	{
+	    printGivenLevel(root, i);
+	}
+
+    }
+
+    //Function to calculate height of Tree
+    fun height(Node: root):void
+    {
+        if (root == null)
+	{
+	     return 0;
+	}
+        else
+        {
+            // compute  height of each subtree 
+            int lheight = height(root.left);
+            int rheight = height(root.right);
+	    // use the larger one 
+            if (lheight > rheight)
+	    {
+		return(lheight + 1);
+	    }
+            else 
+	    {
+	        return(rheight + 1);
+	    }
+        }
+    }
+
+    fun printGivenLevel(Node:root ,int: level):void
+    {
+        if (root == null)
+	{
+	    return;
+	}
+	//Print data
+        if (level == 1)
+	{
+           println(root.data);
+	}
+        else if (level > 1)
+        {
+            printGivenLevel(root.left, level-1);
+            printGivenLevel(root.right, level-1);
+        }
+    }
+
+    fun main()
+    {
+       BinaryTree tree = new BinaryTree();
+       var read = Scanner(System.`in`)
+       println("Enter the size of Array:")
+       val arrSize = read.nextLine().toInt()
+       var arr = IntArray(arrSize)
+       println("Enter data of  binary tree")
+
+       for(i in 0 until arrSize)
+       {
+          arr[i] = read.nextLine().toInt()
+          tree.root = new Node(arr[i]);
+       }
+
+       println("Level order traversal of binary tree is ");
+       tree.printLevelOrder();
+    }
+}
+
+/*
+Input:
+1 2 3 4 5 6 7 8 9
+Output:
+Level order traversal of binary tree is
+1 2 3 4 5 6 7 8 9
+*/