Find the diameter of a binary tree

Question

I am trying to find the diameter of a binary tree (Path length between any two nodes in the tree containing maximum number of nodes.) in java.

my code snippet:

Answer 1

Diameter of a Binary Tree in O(n), It will track the diameter passing through root node or not and uses the same height function to track the diameter.

DiameterOfTree.class

import BinaryTree.BinaryTreeNode;

public class DiameterOfBinaryTree {
    private int DIAMETER = 0;

    public void getDiameterOfBinaryTree(BinaryTreeNode node) {
        getHeightUtil(node, DIAMETER);
        System.out.print("\n\n Maximum Diameter of the tree is : " + DIAMETER);
    }

    private int getHeightUtil(BinaryTreeNode node, Integer maXValue) {
        if (node == null) {
            return 0;
        }

        // Here we get the maximum value returned + 1 for each subtree left or 
        //  right 
        int leftHeight = getHeightUtil(node.getLeft(), maXValue); 
        int rightHeight = getHeightUtil(node.getRight(), maXValue);

        //finding the new diameter at a particular node and adding 1 to 
        //include that particular node as well: leftHeight + rightHeight + 1 
        DIAMETER = Math.max(DIAMETER, leftHeight + rightHeight + 1);

        return 1 + Math.max(leftHeight, rightHeight);
    }
}

Main.java

package BinaryTree;

public class Main {

    public static void main(String[] args) {
        //Initialise root
        BinaryTreeNode root = new BinaryTreeNode(40);

        //Create a binary Tree
        InitialiseBinaryTree initialiseBinaryTree = new InitialiseBinaryTree();
        initialiseBinaryTree.initialise(root);

        // Find the diameter of the binary tree 
        new DiameterOfBinaryTree().getDiameterOfBinaryTree(root);
    }

}

InitialiseBinaryTree.java

package BinaryTree;

class InitialiseBinaryTree {
    void initialise(BinaryTreeNode root) {
        BinaryTreeOperation bto = new BinaryTreeOperation();
        int[] data = {20, 50, 10, 30, 5,8, 25, 32, 33};
        for (int aData : data) {
            bto.insertElementInBinaryTree(root, aData);
        }
    }
}

BinaryTreeOperation.java

package BinaryTree;

class BinaryTreeOperation {
    private boolean findInBinaryTree(BinaryTreeNode node, int data) {
        return node != null &&
                (data == node.getData() || (findInBinaryTree(node.getLeft(), data) || findInBinaryTree(node.getRight(), data)));
    }

    void insertElementInBinaryTree(BinaryTreeNode node, int data) {
        if (node == null) {
            new BinaryTreeNode(data);
        } else {
            insertHelper(node, data);
        }
    }

    private void insertHelper(BinaryTreeNode node, int data) {
        if (node.getData() > data) {
            if (node.getLeft() == null) {
                node.setLeft(new BinaryTreeNode(data));
            } else {
                insertHelper(node.getLeft(), data);
            }
        } else {
            if (node.getRight() == null) {
                node.setRight(new BinaryTreeNode(data));
            } else {
                insertHelper(node.getRight(), data);
            }
        }
    }
}