leetcode 第二题
Maximum Depth of Binary Tree
题目地址:https://leetcode.com/problems/maximum-depth-of-binary-tree/ (opens in a new tab)
Given a binary tree, find its maximum depth. The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node. 题目描述:找出二叉树中最深节点的深度
利用递归即可。
Ruby 版:
# Definition for a binary tree node.
# class TreeNode
# attr_accessor :val, :left, :right
# def initialize(val)
# @val = val
# @left, @right = nil, nil
# end
# end
# @param {TreeNode} root
# @return {Integer}
def max_depth(root)
root.nil? ? 0 : [max_depth(root.left) + 1, max_depth(root.right) + 1].max
end