diameter-of-binary-tree.md

Approach

• Related to Maximum Depth Problem
• Recursive Solution
  1. For each node, find max of each left_depth & right_depth
  2. For each node, diameter = left_diameter + right_diameter
  3. Return max of all diameters (longest path might not be from the top node)

var diameterOfBinaryTree = function(root) {
    if(root == null) return 0
    
    var depth = function(root) {
        if(root == null) return 0
        return Math.max(depth(root.left),depth(root.right)) + 1
    }
    
    let diameter = depth(root.left) + depth(root.right)
    let left_diameter = diameterOfBinaryTree(root.left)
    let right_diameter = diameterOfBinaryTree(root.right)
    return Math.max(diameter,Math.max(left_diameter,right_diameter))
};

Result

• Runtime: 92 ms, faster than 8.97% of JavaScript online submissions for Diameter of Binary Tree.
• Memory Usage: 37.6 MB, less than 12.50% of JavaScript online submissions for Diameter of Binary Tree.

Reference: https://www.youtube.com/watch?v=ey7DYc9OANo