树的子结构

 1 /*
 2 struct TreeNode {
 3     int val;
 4     struct TreeNode *left;
 5     struct TreeNode *right;
 6     TreeNode(int x) :
 7             val(x), left(NULL), right(NULL) {
 8     }
 9 };*/
10 class Solution {
11 public:
12     bool HasSubtree(TreeNode* pRoot1, TreeNode* pRoot2)
13     {
14         bool res=false;
15         if(pRoot1!=NULL&&pRoot2!=NULL){
16             if(pRoot1->val==pRoot2->val)
17                 res=isSubtree(pRoot1,pRoot2);
18             if(!res)
19                 res=HasSubtree(pRoot1->left,pRoot2);
20             if(!res)
21                 res=HasSubtree(pRoot1->right,pRoot2);
22         }
23         return res;
24     }
25 private:
26     bool isSubtree(TreeNode* pRoot1, TreeNode* pRoot2){
27         if(pRoot2==NULL) return true;
28         if(pRoot1==NULL) return false;
29         if(pRoot1->val==pRoot2->val)
30             return isSubtree(pRoot1->left,pRoot2->left)&&isSubtree(pRoot1->right,pRoot2->right);
31         return false;
32     }
33 };