LeetCode-in-All
543. Diameter of Binary Tree
Easy
Given the root of a binary tree, return 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.
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
Constraints:
- The number of nodes in the tree is in the range
[1, 104]. -100 <= Node.val <= 100
Solution
/**
* Definition for a binary tree node.
* function TreeNode(val, left, right) {
* this.val = (val===undefined ? 0 : val)
* this.left = (left===undefined ? null : left)
* this.right = (right===undefined ? null : right)
* }
*/
/**
* @param {TreeNode} root
* @return {number}
*/
var diameterOfBinaryTree = function(root) {
let diameter = 0
const diameterOfBinaryTreeUtil = (node) => {
if (node === null) {
return 0
}
const leftLength = node.left ? 1 + diameterOfBinaryTreeUtil(node.left) : 0
const rightLength = node.right ? 1 + diameterOfBinaryTreeUtil(node.right) : 0
diameter = Math.max(diameter, leftLength + rightLength)
return Math.max(leftLength, rightLength)
}
diameterOfBinaryTreeUtil(root)
return diameter
};
export { diameterOfBinaryTree }