// Package q104 implements a solution for https://leetcode.com/problems/maximum-depth-of-binary-tree/ package q104 type TreeNode struct { Val int Left *TreeNode Right *TreeNode } func md(d int, node *TreeNode) int { if node == nil { return d - 1 } return max(md(d+1, node.Left), md(d+1, node.Right)) } func maxDepth(root *TreeNode) int { return md(1, root) } var _ = maxDepth