LeetCode-559. Maximum Depth of N-ary Tree

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:

1. The depth of the tree is at most 1000.
2. The total number of nodes is at most 5000.

题目:N叉树的深度。

思路：类比二叉树的最大深度，同样采用递归的思路。与而二叉树不同的是，二叉树求解子节点时，只有左右两个孩子节点，而这里孩子节点是一个vector，因此需要递归这个vector中每一个元素，返回最大的depth+1即可。具体实现如下：

class Solution {
public:
    int maxDepth(Node* root) {
        if(!root)
        	return 0;
        else{
        	if(root->children.size() == 0)
        		return 1;
        	else{
        		int length = root->children.size();
        		vector<int> depth(length); //用一个临时vector来记录每个节点的深度
        		for(int i=0;i<length;i++){
        			depth[i] = maxDepth(root->children[i]);
				}
				return *max_element(depth.begin(),depth.end())+1;//返回孩子节点的最大深度+1
			}	
		}	
    }
};

AC,beats 93%