diameterTree.js

// 543. Diameter of Binary Tree

// 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

var diameterOfBinaryTree = function(root) {
    let result = 0
    

    function dfs(root){
        if(!root){
            return -1
        }
        let left = dfs(root.left)
        let right = dfs(root.right)
        result = Math.max(result, left+right +2)
        return Math.max(left, right)+1
    }
    dfs(root)
    return result
};