解題思路:
(1)注意這裏的樹的子結構和劍指offer裏面定義的不一樣
(2)這裏指的是以某個節點作爲根結點,剩下的所有點值均相同,也就是說一直到最後的葉子結點
/**
* 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* s, TreeNode* t) {
if(s==NULL || t==NULL) return false;
else return comp(s,t)||isSubtree(s->left,t)||isSubtree(s->right,t);
}
bool comp(TreeNode* s, TreeNode* t) {
if(s==NULL && t==NULL) return true;
if(s==NULL || t==NULL) return false;
if(s->val!=t->val) return false;
else return comp(s->left,t->left)&&comp(s->right,t->right);
}
};