maximum-depth-of-n-ary-tree.java

// 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, 104].
// 	The depth of the n-ary tree is less than or equal to 1000.
//
//


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

    public Node() {}

    public Node(int _val,List<Node> _children) {
        val = _val;
        children = _children;
    }
};
*/
class Solution {
    public int maxDepth(Node root) {
        if (root == null) return 0;
        int result = 0;
        for (Node child : root.children) result = Math.max(result, maxDepth(child));
        return result + 1;
    }
}