coding-Interview/DiameterBinaryTree.java at master · arjunmullick/coding-Interview · GitHub

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package com.leetcode;

public class DiameterBinaryTree {

//https://leetcode.com/problems/diameter-of-binary-tree/

class Solution {

int max;

public int diameterOfBinaryTree(TreeNode root) {

max = Integer.MIN_VALUE;

if(root == null) return 0;

getDepth(root);

return max == Integer.MIN_VALUE ? 0 : max;

}

public int getDepth(TreeNode node){

if(node == null) return 0;

if(node.left == null && node.right == null) return 1;

int leftDepth = getDepth(node.left);

int rightDepth = getDepth(node.right);

int depth = Math.max(leftDepth,rightDepth);// if both leaf 2 count, counting self so L+R+1 not needed.

max = Math.max(leftDepth+rightDepth , max);

return depth+1;

}

//Definition for a binary tree node.

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;

}

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