二叉树深度

import java.util.Queue;
import java.util.LinkedList;
/**
public class TreeNode {
    int val = 0;
    TreeNode left = null;
    TreeNode right = null;

    public TreeNode(int val) {
        this.val = val;

    }

}
*/
public class Solution {
    /**
    
        递归方法求二叉树的深度
    **/
    public int TreeDepth(TreeNode root) {
        if(root == null) return 0;
        int left = TreeDepth(root.left);
        int right = TreeDepth(root.right);
        return Math.max(left,right) + 1;
       
    }
    //非递归算法
    public int treeDepth(TreeNode root){
        if(root == null) return 0;
        Queue<TreeNode> queue = new LinkedList<TreeNode>();
        int level = 0,count = 0,nextCount = 1;
        queue.add(root);
        while(!queue.isEmpty()){
            TreeNode top = queue.poll();
            if(top.left != null) queue.add(top.left);
            if(top.right != null) queue.add(top.right);
            count++;
            if(count == nextCount){
                nextCount = queue.size();
                count = 0;
                level++;
            }
        }
        return level;
    }
}