Nilesh Raut

Posted on

# #Leetcode 1361: Validating Binary Tree Nodes (Medium)

Introduction

When it comes to tackling complex problems in computer science, Leetcode is the go-to platform for many of us. Today, we're going to dive into one such problem, Leetcode 1361, titled "Validate Binary Tree Nodes." Don't let the 'medium' difficulty label intimidate you – we're here to break it down, step by step.

## Leetcode 1361. Validate Binary Tree Nodes (Medium) : NileshBlog.Tech

Validate Binary Tree Nodes with Leetcode 1361 - Ensure your binary tree structure is accurate and error-free. Solve the challenge today!

nileshblog.tech

Prerequisites

Before we embark on this coding adventure, let's ensure we're on the same page. To tackle Leetcode 1361, it's helpful to have a basic understanding of binary trees and how they work. If you're unfamiliar with the concept, don't worry – we'll provide a quick refresher.

Understanding the Main Concept

The task at hand is to validate a binary tree. A binary tree is a hierarchical data structure that consists of nodes connected by edges. Each node can have, at most, two child nodes, a left child and a right child. For a binary tree to be valid, it must meet specific criteria:

1. There should be exactly one root node.
2. Each node, except the root, should have exactly one parent.
3. There should be no cycles (i.e., no loops) in the tree.
4. The tree should be connected, meaning every node can be reached from the root node.

Now, let's translate these criteria into a coding problem.

Explaining with an Example

Let's take a simple example to illustrate this. Suppose we have the following tree:

``````       0
/ \
2   3
/ \
1   4
``````

In this case, node 0 is the root, and it has two children, 2 and 3. Node 2, in turn, has children 1 and 4. This tree satisfies all the criteria for a valid binary tree.

Step-by-Step Example

To validate whether a given set of nodes forms a binary tree, we can follow these steps:

1. Initialize two arrays to keep track of parent and children for each node.
2. Iterate through all nodes and their children.
3. For each node, check if it has more than one parent. If so, it's not a valid binary tree.
4. For each child, check if it has more than one parent. If so, it's not a valid binary tree either.
5. Check if there is exactly one node with no parent; this should be the root.
6. Ensure that the root node can reach all other nodes.

By following these steps, you can tackle Leetcode 1361: Validating Binary Tree Nodes and conquer the world of binary trees. Happy coding!