合并两个有序链表 - lifengyu360/lifengyu_first_git_test GitHub Wiki

ListNode* mergeTwoLists(ListNode* l1, ListNode* l2) {
    ListNode dummy;
    ListNode *tail = &dummy;
    while (l1 != nullptr && l2 != nullptr) {
        if (l1->val <= l2->val) {
            tail->next = l1;
            l1 = l1->next;
        } else {
            tail->next = l2;
            l2 = l2->next;
        }
        tail = tail->next;
    }
    if (l1 == nullptr) {
        tail->next = l2;
    } else {
        tail->next = l1;
    }
    return dummy.next;
}