/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:
  //第二层对比子树
    bool compare(TreeNode* cur, TreeNode* subRoot)
    {
        if(cur==nullptr && subRoot==nullptr) return true;
        else if(cur == nullptr && subRoot != nullptr) return false;
        else if(cur != nullptr && subRoot == nullptr) return false;
        if(cur->val != subRoot->val) return false;
        bool left_val = compare(cur->left,subRoot->left);
        bool right_val = compare(cur->right,subRoot->right);
        return left_val&right_val;
    }
    //第一层前序遍历看点
    void traversal(TreeNode* cur, TreeNode* subRoot , bool &val)
    {
            if(cur==nullptr) return;
            bool mid_val = compare(cur,subRoot);//调用第二层递归
            //cout<<mid_val<<endl;
            val = val | mid_val ;
            traversal(cur->left , subRoot ,val);
            traversal(cur->right , subRoot ,val);
    }
    bool isSubtree(TreeNode* root, TreeNode* subRoot) {
        bool val = false;
        traversal(root,subRoot,val);
        return val;
    }
};