559. Maximum Depth of N-ary Tree（N叉树的最大深度）

题目描述

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.

For example, given a 3-ary tree:

We should return its max depth, which is 3.

Note:
The depth of the tree is at most 1000.
The total number of nodes is at most 5000.

方法思路

class Solution {
    //Runtime: 2 ms, faster than 99.95%
    //Memory Usage: 44.7 MB, less than 41.44%
    public int maxDepth(Node root) {
        if(root == null) return 0;
        int root_depth = 0;
        for(Node node : root.children){
            int temp = maxDepth(node);
            if(temp > root_depth)
                root_depth = temp;
        }
        return root_depth + 1;
    }
}