合并两个排序的链表
/*
struct ListNode {
int val;
struct ListNode *next;
ListNode(int x) :
val(x), next(NULL) {
}
};*/
class Solution {
public:
ListNode* Merge(ListNode* pHead1, ListNode* pHead2)
{
if (!pHead1) return pHead2;
else if (!pHead2) return pHead1;
if (pHead1->val < pHead2->val) {
pHead1->next = Merge(pHead1->next, pHead2);
return pHead1;
} else {
pHead2->next = Merge(pHead1, pHead2->next);
return pHead2;
}
}
};
