Given a n-ary 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.

Nary-Tree input serialization is represented in their level order traversal, each group of children is separated by the null value (See examples).

Example 1:

Input: root = [1,null,3,2,4,null,5,6] Output: 3 

Example 2:

Input: root = [1,null,2,3,4,5,null,null,6,7,null,8,null,9,10,null,null,11,null,12,null,13,null,null,14] Output: 5 

Constraints:

• The total number of nodes is in the range [0, 10000].
• The depth of the n-ary tree is less than or equal to 1000.

给定一个 N 叉树，找到其最大深度。

最大深度是指从根节点到最远叶子节点的最长路径上的节点总数。

N 叉树输入按层序遍历序列化表示，每组子节点由空值分隔（请参见示例）。

• 使用广度优先遍历

package leetcode typeNodestruct { ValintChildren []*Node } funcmaxDepth(root*Node) int { ifroot==nil { return0 } return1+bfs(root) } funcbfs(root*Node) int { varq []*Nodevardepthintq=append(q, root.Children...) forlen(q) !=0 { depth++length:=len(q) forlength!=0 { ele:=q[0] q=q[1:] length--ifele!=nil&&len(ele.Children) !=0 { q=append(q, ele.Children...) } } } returndepth }