题解 | #合并两个排序的链表#

尾插法

新建前置头指针vhead，尾指针cur并初始化为vhead。若两链表均为遍历完，则把值小的尾插到vhead中。当其中一个链表遍历完后，就把另一个链表链接到vhead后面。

C++代码：

class Solution {
public:
    ListNode* Merge(ListNode* pHead1, ListNode* pHead2) {
        ListNode *vhead = new ListNode(-1), *cur = vhead;
        while (pHead1 && pHead2) {
            if (pHead1->val < pHead2->val) {
                cur->next = pHead1;
                pHead1 = pHead1->next;
            } else {
                cur->next = pHead2;
                pHead2 = pHead2->next;
            }
            cur = cur->next;
        }
        cur->next = pHead1 == NULL ? pHead2 : pHead1;
        return vhead->next;
    }
};