leetcode求二叉树深度

输入一棵二叉树，求该树的深度。从根结点到叶结点依次经过的结点（含根、叶结点）形成树的一条路径，最长路径的长度为树的深度。

非递归写法：层次遍历
import java.util.Queue;
import java.util.LinkedList;
 
public class Solution {
    public int TreeDepth(TreeNode pRoot)
    {
        if(pRoot == null){
            return 0;
        }
        Queue<TreeNode> queue = new LinkedList<TreeNode>();
        queue.add(pRoot);
        int depth = 0, count = 0, nextCount = 1;
        while(queue.size()!=0){
            TreeNode top = queue.poll();
            count++;
            if(top.left != null){
                queue.add(top.left);
            }
            if(top.right != null){
                queue.add(top.right);
            }
            if(count == nextCount){
                nextCount = queue.size();
                count = 0;
                depth++;
            }
        }
        return depth;
    }
}

递归写法:
public class Solution {
    public int TreeDepth(TreeNode root) {
                if(root==null){
            return 0;
        }
           
        int nLelt=TreeDepth(root.left);
        int nRight=TreeDepth(root.right);
         
        return nLelt>nRight?(nLelt+1):(nRight+1);
    }
}