class TreeNode{
int val;//当前节点的值
TreeNode left; //左节点
TreeNode right;//右节点
TreeNode(int x){
val=x;//通过构造方法传值
}
}
public class haha{
public static int maxDepth(TreeNode root){
if(root==null)
return 0;
return 1+Math.max(maxDepth(root.left),maxDepth(root.right));
}
public static void main(String[] args) {
TreeNode root=new TreeNode(3);
TreeNode t1=new TreeNode(5);
TreeNode t2=new TreeNode(7);
t1.left=t2;
TreeNode t3=new TreeNode(9);
root.left=t1;
root.right=t3;
System.out.println(maxDepth(root));
}
}