二叉树的深度

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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;

    }

}

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import java.lang.Math;

public class Solution {

    public int TreeDepth(TreeNode pRoot)

    {

        if(pRoot ==null){

            return 0;

        }

        int left = TreeDepth(pRoot.left);

        int right = TreeDepth(pRoot.right);

        return Math.max(left, right) +1;

    }

}