559+maxDepth_Rec.cpp

/*
// 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) {
        if (root == NULL) return 0;
        int maxD = 0;

        for (int i = 0; i < root->children.size(); ++i) {
            /*
            int depth = maxDepth(root->children[i]);
            maxD = depth>maxD ? depth : maxD;
            */
            maxD = max(maxDepth(root->children[i]), maxD);
        }
        return 1 + maxD;
    }
};