力扣每日一题2021-11-21N叉树的最大深度

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559.N叉树的最大深度

题目描述

N叉树的最大深度

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思路

dfs递归

每个节点的最大深度由它所有子结点的最大深度的最大值决定。

Python实现

"""
# Definition for a Node.
class Node:
    def __init__(self, val=None, children=None):
        self.val = val
        self.children = children
"""

class Solution:
    def maxDepth(self, root: 'Node') -> int:
        return max(self.maxDepth(child) for child in root.children) + 1 if root and root.children else int(root != None)

Java实现

/*
// Definition for a Node.
class Node {
    public int val;
    public List<Node> children;

    public Node() {}

    public Node(int _val) {
        val = _val;
    }

    public Node(int _val, List<Node> _children) {
        val = _val;
        children = _children;
    }
};
*/

class Solution {
    public int maxDepth(Node root) {
        if (root == null) return 0;
        int ans = 0;
        for (Node child: root.children) {
            ans = Math.max(ans, maxDepth(child));
        }
        return ans + 1;
    }
}