D55 429. N-ary Tree Level Order Traversal

题目链接

429. N-ary Tree Level Order Traversal

题目分析

按层遍历N叉树。

思路

以层数为键，塞入当前节点的值。

递归遍历即可。

最终代码

<?php/*// Definition for a Node.class Node {    public $val;    public $children;    @param Integer $val     @param list<Node> $children     function __construct($val, $children) {        $this->val = $val;        $this->children = $children;    }}*/class Solution {    /**     * @param Node $root     * @return Integer[][]     */    public $level = 0;    public $values = [];    function levelOrder($root) {        if(is_null($root)){            return $this->values;        }                if(!isset($this->values[$this->level])){            $this->values[$this->level] = [];        }        $this->values[$this->level][] = $root->val;        foreach($root->children as $child){            $this->level++;            $this->levelOrder($child);            $this->level--;        }                return $this->values;    }}

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