二叉树的深度

/**
public class TreeNode {
    int val = 0;
    TreeNode left = null;
    TreeNode right = null;

    public TreeNode(int val) {
        this.val = val;
    }
}
*/
public class Solution {
    public int TreeDepth(TreeNode root) {
        if(root==null){
            return 0;
        }
        int left=TreeDepth(root.left);
        int right=TreeDepth(root.right);
        return left>right?left+1:right+1;
    }
}