559. Maximum Depth of N-ary Tree

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559. Maximum Depth of N-ary Tree

Description

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:

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

Example 2:

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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, 10^4].
  • The depth of the n-ary tree is less than or equal to 1000.

Hints/Notes

Solution

Language: C++

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

    Node() {}

    Node(int _val) {
        val = _val;
    }

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

class Solution {
public:
    int maxDepth(Node* root) {
        return find(root, 1);
    }

    int find(Node* root, int depth) {
        if (!root) {
            return 0;
        }
        int res = depth;
        for (auto child : root->children) {
            res = max(res, find(child, depth + 1));
        }
        return res;
    }
};