yaaaaaa's fucking hard coding ><.cpp

#include <iostream>
#include <string>
#include <stdexcept>

using namespace std;

class ListNode{
private:
    int data;
    ListNode *next;
    ListNode *prev;
public:
    ListNode():data(0),next(nullptr), prev(nullptr){};
    ListNode(int a):data(a),next(nullptr), prev(nullptr){};

    friend class List;
};

class List {
private:
    ListNode* head;  // head of the doubly linked list
    ListNode* tail;  // tail of the doubly linked list
    ListNode* middle; // middle of the list
    int       cnt;   // total count of the elements in the list
    int       pos;   // the position of middle

    void reset(){
        head = nullptr;
        tail = nullptr;
        middle = nullptr;
        cnt = 0;
        pos = 0;
    }

    void clean(){
        ListNode* temp;
        while(head!=nullptr){
            temp = head;
            head = head->next;
            delete temp;
        }
    }

public:
    // constructor and destructor
    List(){
        reset();
    }

    ~List(){
        clean();
    }

    void InsertHead(int data){
		cnt++;
		if(head == nullptr){
			head = new ListNode(data);
			tail = head;
			middle = head;
		}else{
			head->prev = new ListNode(data);
			head->prev->next = head;
			head = head->prev;
			if(tail == nullptr) cout << "kao yao o" << endl;
			if(cnt%2 == 1) middle = middle->prev;
		}
	}
    int  RemoveHead(){
		if(head == nullptr) throw out_of_range("123");
		else{
			cnt--;
			ListNode *bye = head;
			int ans = head->data;
			head = head->next;
			delete bye;
			if(cnt != 0){
				head->prev = nullptr;
				if(cnt%2 == 0)
					middle = middle->next;
			}else{
				tail = nullptr;
				middle = nullptr;
			}
			return ans;
		}
	}
    void InsertTail(int data){
		cnt++;
		if(head == nullptr){
			head = tail = middle = new ListNode(data);
		}else{
			ListNode* tmp = new ListNode(data);
			tmp->prev = tail;
			tail->next = tmp;
			tail = tmp;
			if(cnt%2 == 0) middle = middle->next;
		}
	}
    int  RemoveTail(){
		if(cnt == 0) throw out_of_range("123");
		else{
			cnt--;
			int ans = tail->data;
			ListNode *bye = tail;
			tail = tail->next;
			delete bye;
			if(cnt != 0){
				tail->next = nullptr;
				if(cnt%2 == 1)
					middle = middle->prev;
			}else{
				head = nullptr;
				middle = nullptr;
			}
		}
	}
    void Swap(){
		if(head != nullptr){
			ListNode *tmp;
			if(cnt%2 == 0) tmp = head;
			else tmp = tail;
			tail->next = head;
			head->prev = tail;
			tail = middle->prev;
			tail->next = nullptr;
			head = middle;
			head->prev = nullptr;
			middle = tmp;
		}
	}
    int  getSize();
    int  getMiddle();
	void show_tail(){
		ListNode *tmp = tail;
		while(tail != nullptr){
			cout << tail->data << " ";
			tail = tail->prev;
		}
		cout << endl;
	}

};

int main(){
    List L;
    string cmd;
    int data, cnt=0, pos = 0;

    while(cin >> cmd){
        if(cmd=="IH"){ // insert an integer to the head
            cin >> data;
            L.InsertHead(data);
        } else if (cmd=="IT"){ // insert an integer to the end
            cin >> data;
            L.InsertTail( data);
        } else if (cmd=="RH"){   // print and remove a node from head
            try {
                cout<< L.RemoveHead() <<endl;
            } catch (const out_of_range &e){
                cout << endl;
            }
        } else if (cmd=="RT") {// print and remove a node from tail
            try {
                cout << L.RemoveTail()<<endl;
            } catch (const out_of_range &e){
                cout << endl;
            }
        } else if (cmd=="S"){
            L.Swap();
        }
		L.show_tail();
    }
}