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) {
        ListNode * head = new ListNode(-1);
        ListNode * last = head;
		if (pHead1 == nullptr && pHead2 == nullptr) {
			return nullptr;
		}
		while (pHead1 && pHead2) {
			if (pHead1->val <= pHead2->val) {
				last->next = pHead1;
				pHead1 = pHead1->next;
			}else {
				last->next = pHead2;
				pHead2 = pHead2->next;
			}
			last = last->next;

		}
		if (pHead1) {
			last->next = pHead1;
		}
		if (pHead2) {
			last->next = pHead2;
		}
		return head->next;
    }
};