/**public class TreeNode {    int val = 0;    TreeNode left = null;    TreeNode right = null;    public TreeNode(int val) {        this.val = val;    }}*//*输入两棵二叉树A，B，判断B是不是A的子结构。（ps：我们约定空树不是任意一个树的子结构）*/public class Solution {    public boolean HasSubtree(TreeNode root1,TreeNode root2) {        if(root1==null || root2==null) return false;        return fun(root1,root2)||fun(root1.left,root2)||fun(root1.right,root2);    }    public boolean fun(TreeNode node1, TreeNode node2) {        if(node2 == null) return true;        else if(node1 == null) return false;        else if(node1.val != node2.val) return false;        return fun(node1.left,node2.left)&&fun(node1.right,node2.right);    }}