leetcode559N叉树的最大深度（java实现）

/*
// 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;
       else
       {
           int num_children = root.children.size();//重要！
           int i,max=0;
           if(num_children>0)
           {
               for(i=1,max=maxDepth(root.children.get(0));i<num_children;i++)
                  if(maxDepth(root.children.get(i))>max)//c语言直接用array[i]，java需要用.get(i)方法获取成员
                     max=maxDepth(root.children.get(i));
           }    
           

                                
           return max+1;
       }
    }
}