Leetcode•May 20, 2025
Diameter of Binary Tree
Hazrat Ali
Leetcode
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.
The length of a path between two nodes is represented by the number of edges between them.
Example 1:
Input: root = [1,2,3,4,5] Output: 3 Explanation: 3 is the length of the path [4,2,1,3] or [5,2,1,3].
Example 2:
Input: root = [1,2] Output: 1
Solution
/**
* @param {TreeNode} root
* @return {number}
*/
const diameterOfBinaryTree = root => {
const helper = root => {
if (!root) {
return 0;
}
const left = helper(root.left);
const right = helper(root.right);
max = Math.max(max, 1 + left + right);
return 1 + Math.max(left, right);
};
let max = 0;
helper(root);
return max;
};