using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp1
{
    public sealed class ScientistsList
    {
        private NodeScientist head; // Start of list
        private NodeScientist tail; // End of list
        private NodeScientist link;  // List link to other node

        public ScientistsList()
        {
            head = null;
            tail = null;
            link = null;
        }

        public void Remove()
        {
            while (head != null)
            {
                link = head;
                head = head.Link;
                link.Link = null;
            }
            tail = link = head;
        }

        public void GetHead(Scientist newScientist)
        {
            head = new NodeScientist(newScientist, head);
        }

        public void SetData(Scientist newScientist)
        {
            var temp = new NodeScientist(newScientist, null);
            if(head != null)
            {
                tail.Link = temp;
                tail = temp;
            }
            else
            {
                head = temp;
                tail = temp;
            }
        }

        public void Sort()
        {
            for(NodeScientist i = head.Link; i.Link != null; i = i.Link)
            {
                NodeScientist max = i;
                for(NodeScientist j = i.Link; j.Link != null; j = j.Link)
                {
                    if (j.Data < max.Data)
                    {
                        max = j;
                    }
                }
                Scientist temp = i.Data;
                i.Data = max.Data;
                max.Data = temp;
            }
        }


        public void Start() { link = head; }
        public void Next() { link = link.Link; }
        public bool Exists() { return link != null; }
        public void Finish() { link = tail; }
        public Scientist GetData() { return link.Data; }

        public bool Contains(Scientist scientist)
        {
            bool temp = false;
            for(NodeScientist i = head; i != null; i = i.Link)
            {
                if (i.Data.Equals(scientist))
                    temp = true;
            }
            return temp;
        }
    }
}