合并两个排序的链表

题目描述

输入两个单调递增的链表，输出两个链表合成后的链表，当然我们需要合成后的链表满足单调不减规则。

​​https://www.nowcoder.com/practice/d8b6b4358f774294a89de2a6ac4d9337?tpId=13&tqId=11169&rp=1&ru=/ta/coding-interviews&qru=/ta/coding-interviews/question-ranking​​

题解：

class Solution {
public:
    ListNode* Merge(ListNode* pHead1, ListNode* pHead2)
    {
        ListNode *p = new ListNode(0);
        ListNode *res = p;
        while (pHead1 != NULL && pHead2 != NULL) {
            if (pHead1->val < pHead2->val) {
                p->next = new ListNode(pHead1->val);
                p = p->next;
                pHead1 = pHead1->next;
            }
            else {
                p->next = new ListNode(pHead2->val);
                p = p->next;
                pHead2 = pHead2->next;
            }
        }
        while (pHead1 != NULL) {
            p->next = new ListNode(pHead1->val);
            p = p->next;
            pHead1 = pHead1->next;
        }
        while (pHead2 != NULL) {
            p->next = new ListNode(pHead2->val);
            p = p->next;
            pHead2 = pHead2->next;
        }
        return res->next;
    }
};