由於是排好序的佇列,所以處理起來相對簡單

ListNode* deleteDuplicates(ListNode* head) {
    ListNode*l2=new ListNode(0);
    if(head==NULL)
        return head;

    if(head!=NULL&&head->next==NULL)
        return head;
    ListNode *l3=l2;
    ListNode*last=head;
    head=head->next;

    int flag=0;
    while(head!=NULL){
        if(head->val!=last->val){
            if(flag==0) {
                l2->next = last;
                l2=l2->next;
                last = head;
                head = head->next;
            }else
            {
                if(head->next==NULL){
                    l2->next=head;
                    head=head->next;
                }else {
                    flag = 0;
                    last = head;
                    head = head->next;
                }
            }
        }
        else if(head->val==last->val){
            if(head->next==NULL){
                l2->next=NULL;
                head=head->next;
            }else {
                flag = 1;
                last = head;
                head = head->next;
            }
        }
    }
    return l3->next;
}