0559. Maximum Depth of N Ary Tree

# 559. Maximum Depth of N-ary Tree#

## 题目 #

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.

## 题目大意 #

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

## 代码 #

``````
package leetcode

type Node struct {
Val int
Children []*Node
}

func maxDepth(root *Node) int {
if root == nil {
return 0
}
return 1 + bfs(root)
}

func bfs(root *Node) int {
var q []*Node
var depth int
q = append(q, root.Children...)
for len(q) != 0 {
depth++
length := len(q)
for length != 0 {
ele := q[0]
q = q[1:]
length--
if ele != nil && len(ele.Children) != 0 {
q = append(q, ele.Children...)
}
}
}
return depth
}
``````

Nov 25, 2022