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Detect next node at same level of a key in binary tree in kotlin

Next node of same level of tree

Kotlin program for Detect next node at same level of a key in binary tree. Here more solutions.

/* 
  Kotlin program for
  Find the next node of the key at the same 
  level in the binary tree
*/
// Binary Tree node
class TreeNode
{
	var data: Int;
	var left: TreeNode ? ;
	var right: TreeNode ? ;
	constructor(data: Int)
	{
		// Set node value
		this.data = data;
		this.left = null;
		this.right = null;
	}
}
class BinaryTree
{
	var root: TreeNode ? ;
	var status: Int;
	var result: TreeNode ? ;
	constructor()
	{
		this.root = null;
		this.status = -1;
		this.result = null;
	}
	// Method which are find next node of same level
	fun findNextNode(temp: TreeNode ? , 
                     level : Int, node: Int): Unit
	{
		if (temp != null)
		{
			if (this.status == -1 && temp.data == node)
			{
				// When found node value
				this.status = level;
			}
			else if (this.status == level && this.result == null)
			{
				// Next node of same level
				this.result = temp;
			}
			// Visit to left subtree
			this.findNextNode(temp.left, level + 1, node);
			// Visit to right subtree
			this.findNextNode(temp.right, level + 1, node);
		}
	}
	// This are handling the request of to finding next
	// node in same level by given node
	fun nextNode(node: Int): Unit
	{
		// Reset the result indicator
		this.status = -1;
		this.result = null;
		// Find next node
		this.findNextNode(this.root, 0, node);
		println("\n Node : " + node);
		print(" Result : ");
		// Test Case
		if (this.status == -1)
		{
			// Case A
			// When node values are not exist
			println("Not found");
		}
		else if (this.result == null)
		{
			// Case B
			// When next node is not found
			println("None");
		}
		else
		{
			// Case C
			// When next node are exist
			println(this.result!!.data);
		}
	}
}
fun main(args: Array < String > ): Unit
{
	// Create new tree
	val tree: BinaryTree = BinaryTree();
	/*
	   Make A Binary Tree
	  ---------------------
	        1
	       / \ 
	      /   \ 
	     /     \
	    2       4
	   /       / \
	  /       /   \
	  3      6     5
	   \      \   /
	    7      8 11
	              
	*/
	// Add node in Binary Tree
	tree.root = TreeNode(1);
	tree.root?.left = TreeNode(2);
	tree.root?.left?.left = TreeNode(3);
	tree.root?.left?.left?.right = TreeNode(7);
	tree.root?.right = TreeNode(4);
	tree.root?.right?.right = TreeNode(5);
	tree.root?.right?.right?.left = TreeNode(11);
	tree.root?.right?.left = TreeNode(6);
	tree.root?.right?.left?.right = TreeNode(8);
	// Testing
	tree.nextNode(3);
	tree.nextNode(7);
	tree.nextNode(6);
	tree.nextNode(5);
	tree.nextNode(8);
	tree.nextNode(1);
}

Output

 Node : 3
 Result : 6

 Node : 7
 Result : 8

 Node : 6
 Result : 5

 Node : 5
 Result : None

 Node : 8
 Result : 11

 Node : 1
 Result : None




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