#include <iostream>

using namespace std;
#pragma once

namespace task8 {

	struct Node
	{
	public:
		int key;
		Node* next;
	};

	Node* newNode(int key); 
	Node* rand_list(int size);
	void print_list(Node* head); 
	void cycle(Node*&head, int offset);

	int init()
	{
		int n; cout << "Enter size: "; cin >> n;
		Node* lst = rand_list(n);
		print_list(lst);
		int offset; cout << "Enter offset: "; cin >> offset;

		cycle(lst, offset);
		print_list(lst);

		return 0;
	}

	Node* newNode(int key)
	{
		Node* node = new Node;
		node->key = key;
		node->next = nullptr;
		return node;
	}

	Node* rand_list(int size)
	{
		Node* head = newNode(rand());
		Node* last = newNode(rand());
		head->next = last;

		for (int i = 0; i < size; i++)
		{
			Node* node = newNode(i+1);

			last->next = node;
			last = node;
		}

		return head->next->next;
	}

	void push_back(Node* head, int key)
	{
		Node* last = nullptr;
		Node* ptr = head;
		while (ptr)
		{
			last = ptr;
			ptr = ptr->next;
		}
		ptr = newNode(key);
		last->next = ptr;
	}

	Node* push_forward(Node* head, int key)
	{
		Node* node = newNode(key);
		node->next = head;
		return node;
	}

	void print_list(Node* head)
	{
		Node* ptr = head;
		while (ptr)
		{
			cout << ptr->key << " -> ";
			ptr = ptr->next;
		}
		cout << "nullptr" << endl;
	}

	void cycle(Node*& head, int offset)
	{
		int amt = 0;
		Node* ptr = head;
		while (ptr->next)
		{
			ptr = ptr->next;
			amt++;
		}
		ptr->next = head;
		Node* prv = ptr;

		if (offset < 0)
		{
			offset = abs(amt+1 + offset);
		}

		for (int i = 0; i < offset; i++)
		{
			prv = prv->next;
			head = head->next;
		}
		prv->next = nullptr;

	}
}