【剑指offer】合并两个排序的链表

 1 /*
 2 struct ListNode {
 3     int val;
 4     struct ListNode *next;
 5     ListNode(int x) :
 6             val(x), next(NULL) {
 7     }
 8 };*/
 9 class Solution {
10 public:
11     ListNode* Merge(ListNode* pHead1, ListNode* pHead2)
12     {
13         if(pHead1 == NULL)    return pHead2;
14         else if(pHead2 == NULL)    return pHead1;
15         ListNode* mergeNode = NULL;
16         if(pHead1-> val < pHead2->val){
17             mergeNode = pHead1;
18             mergeNode->next = Merge(pHead1->next,pHead2);
19         }
20         else{
21             mergeNode = pHead2;
22             mergeNode->next = Merge(pHead1,pHead2->next);
23         }
24         return mergeNode;
25     }
26 };