[자료 구조] Doubly Linked List로 CPP STL - 3

#include <iostream>
using namespace std;

struct Node {
    Node* next;
    Node* prev;
    int data;
};

class nodeList {
public:
    nodeList();
    Node* begin();
    Node* end();
    int Size();
    bool isEmpty();
    void insert(Node* pos, const int& e);
    void erase(Node* pos);
    bool nextP(Node* pos);
    bool prevP(Node* pos);
    void finddivisor(const int& e);

private:
    Node* header;
    Node* trailer;
    int size;
};

nodeList::nodeList() {
    header = new Node;
    trailer = new Node;

    header->next = trailer;
    trailer->prev = header;

    header->prev = trailer->next = nullptr;

    size = 0;
}

Node* nodeList::begin() {
    return header->next;
}

Node* nodeList::end() {
    return trailer;
}

int nodeList::Size() {
    return size;
}

bool nodeList::isEmpty() {
    if (size == 0)
        return true;

    return false;
}

void nodeList::insert(Node* pos, const int& e) {
    Node* newNode = new Node;
    newNode->data = e;

    newNode->next = pos;
    newNode->prev = pos->prev;

    pos->prev->next = newNode;
    pos->prev = newNode;
    ++size;
}

void nodeList::erase(Node* pos) {
    if (pos == trailer)
        return;

    pos->prev->next = pos->next;
    pos->next->prev = pos->prev;
    delete pos;
    --size;
}

bool nodeList::nextP(Node* pos) {
    if (pos == trailer)
        return false;

    return true;
}

bool nodeList::prevP(Node* pos) {
    if (pos == header->next)
        return false;

    return true;
}

void nodeList::finddivisor(const int& e) {
    Node* curNode = header->next;

    int idx = 0;
    bool isExist = false;
    while (curNode != trailer) {
        if (e%curNode->data == 0) {
            isExist = true;
            cout << idx << ' ';
        }
        ++idx;
        curNode = curNode->next;
    }
    if (!isExist)
        cout << -1 << '\n';
    else
        cout << '\n';
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);


    int N;
    cin >> N;

    while (N--) {
        nodeList* List = new nodeList;
        Node* p = List->end();
        int e;
        cin >> e;
        for (int i = 0; i < e; ++i) {
            int val;
            cin >> val;
            List->insert(p, val);
            List->end();
        }
        cin >> e;
        p = List->begin();
        int curIndex = 0;
        for (int i = 0; i < e; ++i) {
            int val;
            cin >> val;
            if (val > 0) {
                for (int i = 0; i < val; ++i) {
                    if (p != List->end()) {
                        p = p->next;
                        curIndex++;
                    }
                }
                int tmp = p->data;
                if (tmp > 0) {
                    for (int i = 0; i < tmp; ++i) {
                        if (p != List->end()) {
                            p = p->next;
                            curIndex++;
                        }
                    }
                }
                else {
                    for (int i = 0; i < -tmp; ++i) {
                        if (p != List->begin()) {
                            p = p->prev;
                            curIndex--;
                        }
                    }
                }
            }
            else {
                for (int i = 0; i < -val; ++i) {
                    if (p != List->begin()) {
                        p = p->prev;
                        curIndex--;
                    }
                }
                int tmp = p->data;
                if (tmp > 0) {
                    for (int i = 0; i < tmp; ++i) {
                        if (p != List->end()) {
                            p = p->next;
                            curIndex++;
                        }
                    }
                }
                else {
                    for (int i = 0; i < -tmp; ++i) {
                        if (p != List->begin()) {
                            p = p->prev;
                            curIndex--;
                        }
                    }
                }
            }
        }
        if (curIndex*2 < List->Size()-1) {
            cout << "header" << '\n';
        }
        else if (curIndex*2 > List->Size()-1) {
            cout << "trailer" << '\n';
        }
        else {
            cout << "middle" << '\n';
        }
    }

    return 0;
}