Count-Full-Half-Leaf-Nodes

package com.tree.traversal.recursive;

import java.util.LinkedList;
import java.util.Queue;

public class CountFullHalfLeafNodes {
	static int fullNodes = 0;
	static int halfNodes = 0;
	static int leafNodes = 0;
	public static void main(String[] args) {
		TreeNode left = new TreeNode(2);
		TreeNode right = new TreeNode(3);
		TreeNode root = new TreeNode(1, left, right);
		left.left = new TreeNode(4);
		right.left = new TreeNode(5, new TreeNode(7), null);
		right.right = new TreeNode(7, null, new TreeNode(8));
		
		countNodesRecursive(root);
		System.out.println("Recursive \nFull Nodes -> "+fullNodes);
		System.out.println("Half Nodes -> "+halfNodes);
		System.out.println("Leaf Nodes -> "+leafNodes);
		
		fullNodes = 0; halfNodes = 0; leafNodes = 0; 
		
		countNodesIterative(root);
		System.out.println("\nIterative \nFull Nodes -> "+fullNodes);
		System.out.println("Half Nodes -> "+halfNodes);
		System.out.println("Leaf Nodes -> "+leafNodes);
	}
	
	private static void countNodesIterative(TreeNode root) {
		if(root == null)
			return;
		Queue<TreeNode> q = new LinkedList<>();
		q.add(root);
		while(!q.isEmpty()) {
			TreeNode current = q.remove();
			if(current.left != null && current.right != null) {
				fullNodes++;
				q.add(current.left);
				q.add(current.right);
			}
			else if(current.left != null || current.right != null) {
				halfNodes++;
				q.add(current.left != null ? current.left : current.right);
			}
			else
				leafNodes++;
		}
	}

	private static void countNodesRecursive(TreeNode node)  {
		if(node == null)
			return;
		
		if(node.left != null && node.right != null)
			fullNodes++;
		else if(node.left != null || node.right != null)
			halfNodes++;
		else 
			leafNodes++;
		
		countNodesRecursive(node.left);
		countNodesRecursive(node.right);
	}
}
public class TreeNode {
	int val;
	TreeNode left;
	TreeNode right;

	TreeNode() {
	}

	TreeNode(int val) {
		this.val = val;
	}

	TreeNode(int val, TreeNode left, TreeNode right) {
		this.val = val;
		this.left = left;
		this.right = right;
	}
}