104. Maximum Depth of Binary Tree #

题目 #

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.

Note: A leaf is a node with no children.

Example:

Given binary tree [3,9,20,null,null,15,7],

    3
   / \
  9  20
    /  \
   15   7

return its depth = 3.

题目大意 #

要求输出一棵树的最大高度。

解题思路 #

这一题递归遍历就可，遍历根节点的左孩子的高度和根节点右孩子的高度，取出两者的最大值再加一即为总高度。

代码 #

package leetcode

/**
 * 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
	}
	return max(maxDepth(root.Left), maxDepth(root.Right)) + 1
}