import java.util.*; /* * public class TreeNode { * int val = 0; * TreeNode left = null; * TreeNode right = null; * } */ public class Solution { /** * * @param root TreeNode类 * @return int整型 */ public int maxDepth (TreeNode root) { if(root==null){ return 0; } int line=0; if(root!=null){ line++; } int leftH=maxDepth(root.left); int rightH=maxDepth(root.right); return Math.max(leftH,rightH)+1; } }