lol.cs

using System;
using System.Collections.Generic;

namespace PreExceed_Karaoke
{
    class Program
    {
        static void Main(string[] args)
        {
            List<int> l = new List<int>();
            Dictionary<int, int> d = new Dictionary<int,int>();

            String[] metaStr = Console.ReadLine().Split(' ');
            int classRooms = int.Parse(metaStr[0]);
            int students = int.Parse(metaStr[1]);

            for (int i = 0; i < students; i++)
            {
                String[] dataStr = Console.ReadLine().Split(' ');
                d[int.Parse(dataStr[1])] = int.Parse(dataStr[0]);
            }

            bool a = false;

            for (;;)
            {
                String[] cmdStr = Console.ReadLine().Split(' ');
                if (cmdStr[0] == "E")
                {
                    int afterIndex = -1;
                    int stdid = int.Parse(cmdStr[1]);
                    int myRoom = d[stdid];
                    for (int i = 0; i < l.Count; i++)
                    {
                        int room = d[l[i]];
                        if (room == myRoom)
                        {
                            afterIndex = i;
                        }
                    }
                    if (afterIndex == -1)
                    {
                        l.Add(stdid);
                    }
                    else
                    {
                        l.Insert(afterIndex + 1, stdid);
                    }
                }
                else if (cmdStr[0] == "D")
                {
                    if (l.Count == 0)
                    {
                        Console.WriteLine("empty");
                    }
                    else
                    {
                        Console.WriteLine(l[0]);
                        l.RemoveAt(0);
                    }
                }
                else if (cmdStr[0] == "X")
                {
                    Console.WriteLine("0");
                    Console.ReadLine();
                    return;
                }
            }
        }
    }
}