104. Maximum Depth of Binary Tree

https://leetcode.com/problems/maximum-depth-of-binary-tree/

JavaScript

/**
 * Definition for a binary tree node.
 * function TreeNode(val) {
 *     this.val = val;
 *     this.left = this.right = null;
 * }
 */
/**
 * @param {TreeNode} root
 * @return {number}
 */
function maxDepth(root) {
  if (!root) {
    return 0
  }

  return 1 + Math.max(maxDepth(root.left), maxDepth(root.right))
}

Python

# Definition for a binary tree node.
# class TreeNode(object):
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None


class Solution(object):

    def maxDepth(self, root):
        """
        :type root: TreeNode
        :rtype: int
        """
        return 0 if root is None else 1 + max(self.maxDepth(root.left), self.maxDepth(root.right))

Go

/**
 * Definition for a binary tree node.
 * type TreeNode struct {
 *     Val int
 *     Left *TreeNode
 *     Right *TreeNode
 * }
 */
func maxDepth(root *TreeNode) int {
    if root == nil {
        return 0
    }

    l := maxDepth(root.Left)
    r := maxDepth(root.Right)

    if l > r {
        return l + 1
    }
    return r + 1
}