题解 | #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 == NULL && pHead2 == NULL)
			return NULL;
		if(pHead1 == NULL)
			return pHead2;
		if(pHead2 == NULL)
			return pHead1;
		struct ListNode* p = (struct ListNode*)malloc(sizeof(struct ListNode)); 
    	p->val = -1;
    	struct ListNode *list = p;
		while(pHead1 != NULL && pHead2 != NULL){
			if(pHead1->val <= pHead2->val){
				list->next = pHead1;
				list = list->next;
				pHead1 = pHead1->next;
			}
			else{
				list->next = pHead2;
				list = list->next;
				pHead2 = pHead2->next;
			}
		}
		if(pHead1 == NULL){
			list->next = pHead2;
			return p->next;
		}
		list->next = pHead1;
			return p->next;
    }
};