Diameter of Binary Tree - Leetcode

Given a binary tree, you need to compute the length of the diameter of the tree. The diameter of a binary tree is the length of the longest path between any two nodes in a tree. This path may or may not pass through the root.

Example:
Given a binary tree

          1
         / \
        2   3
       / \     
      4   5    

Return 3, which is the length of the path [4,2,1,3] or [5,2,1,3].
Note: The length of path between two nodes is represented by the number of edges between them.

 /**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
public class Solution {
    int max = 0;
  
    public int diameterOfBinaryTree(TreeNode root) {
        depth(root);
        return max;
    }
  
    private int depth(TreeNode root) {
        if (root == null) return 0;
      
        int left = depth(root.left);
        int right = depth(root.right);
      
        max = Math.max(max, left + right);
      
        return Math.max(left, right) + 1;
    }
}

Try this on Leetcode.

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