In this article, we will discuss how to print nodes at k distance from the root of a binary tree. The trees are hierarchical data structures unlike Arrays, Linked Lists, Stack and queues, which are linear data structures. In the tree, the topmost node is known as the root of the tree. Other elements that are directly under an element are called its children. The element directly above something is called its parent. Let’s see the following diagram of the binary tree data structure:
tree ---- j <-- root / \ f k / \ \ a h z <-- leaves
Let’s see the tree node representation in Java code like the following:
/** * Class containing left and right child of current node and key value */ package com.dineshonjava.algo; /** * @author Dinesh.Rajput * */ public class TreeNode { int data; TreeNode left, right; TreeNode(int item) { data = item; left = right = null; } }
In previous articles we have discussed some important algorithm related to the linked list like the following:
Let’s discuss the algorithm to print nodes at k distance from the root of the binary tree.
Given a root of a tree, and an integer k. Print all the nodes which are at k distance from the root. Let’s see the following code:
/** * */ package com.dineshonjava.algo; /** * @author Dinesh.Rajput * */ public class TreeTest { /** * @param args */ public static void main(String[] args) { TreeNode root = new TreeNode(0); root.left = new TreeNode(1); root.right = new TreeNode(2); root.left.left = new TreeNode(3); root.left.right = new TreeNode(4); root.right.left = new TreeNode(5); root.right.right = new TreeNode(6); root.left.left.left = new TreeNode(7); root.left.left.right = new TreeNode(8); root.left.right.left = new TreeNode(9); root.left.right.right = new TreeNode(10); root.right.left.left = new TreeNode(11); root.right.left.right = new TreeNode(12); root.right.right.left = new TreeNode(13); root.right.right.right = new TreeNode(14); System.out.println("Nodes at 3 distance from the root"); printKDistant(root, 3); } private static void printKDistant(TreeNode node, int k) { if (node == null) return; if (k == 0) { System.out.print(node.data + " "); return; } else { printKDistant(node.left, k - 1); printKDistant(node.right, k - 1); } } }
Run above program, you will get the following output:
Nodes at 3 distance from the root 7 8 9 10 11 12 13 14
As you can see the above output, we have printed all nodes with distance 3.
Hope, you have understood this solution for the above to print nodes at k distance from the root. Please share other solutions if you have. :).
Happy learning with us!!!.
Strategy Design Patterns We can easily create a strategy design pattern using lambda. To implement…
Decorator Pattern A decorator pattern allows a user to add new functionality to an existing…
Delegating pattern In software engineering, the delegation pattern is an object-oriented design pattern that allows…
Technology has emerged a lot in the last decade, and now we have artificial intelligence;…
Managing a database is becoming increasingly complex now due to the vast amount of data…
Overview In this article, we will explore Spring Scheduler how we could use it by…