力扣-572题另一棵树的子树（C++）- 递归+有价值+有100题的思路

谁践踏了优雅 2022-08-28 09:49 158阅读 0赞

题目链接：[https://leetcode-cn.com/problems/subtree-of-another-tree/][https_leetcode-cn.com_problems_subtree-of-another-tree]  
题目如下：  
![在这里插入图片描述][da105d7b5663459eacbd86f69ba391fb.png]  
![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBASkluZ2xlczEyMw_size_20_color_FFFFFF_t_70_g_se_x_16]  
![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBASkluZ2xlczEyMw_size_20_color_FFFFFF_t_70_g_se_x_16 1]  
![在这里插入图片描述][5e3df09180244633997ba384e7d0803c.png]

/**
     * 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:
        bool isSubtree(TreeNode* root, TreeNode* subRoot) {
        
            //遍历完s，还没匹配到，则返回false
            if(root==NULL) return false;
    
            //短路运算符，有一个为真，则返回真
            return dfs(root,subRoot)||isSubtree(root->left,subRoot)||isSubtree(root->right,subRoot);
        }
    
        //此函数为判断两个子树是否相同的函数，同力扣第100题
        bool dfs(TreeNode* p1,TreeNode* p2){
        
            if(p1==NULL&&p2==NULL) return true;
    
            if(p1==NULL&&p2!=NULL) return false;
            if(p1!=NULL&&p2==NULL) return false;
    
            if(p1->val!=p2->val) return false;
    
            return dfs(p1->left,p2->left)&&dfs(p1->right,p2->right);
        }
    };

[https_leetcode-cn.com_problems_subtree-of-another-tree]: https://leetcode-cn.com/problems/subtree-of-another-tree/
[da105d7b5663459eacbd86f69ba391fb.png]: /images/20220828/81aa0a0453c14d8486ac3364300c847a.png
[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBASkluZ2xlczEyMw_size_20_color_FFFFFF_t_70_g_se_x_16]: /images/20220828/bdcb9acab76c49ad967efe61330ed15e.png
[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBASkluZ2xlczEyMw_size_20_color_FFFFFF_t_70_g_se_x_16 1]: /images/20220828/3b16f4910b6449f5b3c0b9a2aba2a7a2.png
[5e3df09180244633997ba384e7d0803c.png]: /images/20220828/98d0aa396c8843d18836381379a6758d.png