HackerRank Stryker code sprint - study code #5

PointFilter_studyCode_E.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;

class Solution {
    static void Main(String[] args) {
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution */
        
        int n,b;
        
        string[] _tokens = Console.ReadLine().Split(' ');
        n=int.Parse(_tokens[0]);
        b=int.Parse(_tokens[1]);
        
        List<Coord> lstC = new List<Coord>();
        List<Coord>  lstB = new List<Coord>();
        List<double> remLst = new List<double>();
        Dictionary<int,Coord> d = new Dictionary<int,Coord>();
        
        while(n-- >0)
            {
             string[] _tokens1 = Console.ReadLine().Split(' ');
             var crd = new Coord();
             crd.K = int.Parse(_tokens1[0]);
            crd.X = double.Parse(_tokens1[1]);
            crd.Y = double.Parse(_tokens1[2]);
            crd.Z = double.Parse(_tokens1[3]);
            d.Add(crd.K,crd);
            lstC.Add(crd);
            
       
        }
        
        lstC = lstC.OrderByDescending(x=>x.Z).ToList();
        
        for(int i=0;i<b;i++)
            {
            lstB.Add(lstC[i]);
        }
        lstC.RemoveRange(0,b);
        
        int ptrC = 0;
        var ipq =Console.ReadLine();
        while(ipq!=null)
            {
            
            string[] q = ipq.Split(' ');
            
            switch(q[0][0])
                {
                case 'F':
                case 'f':
                var k = int.Parse(q[1]);
                
                Coord _c = d[k];
                if(_c==null||(lstB[0].Z<_c.Z||_c.Z<lstB[lstB.Count-1].Z))
                    {
                    Console.WriteLine("Point doesn't exist in the bucket.");
                }
                else
                    {
                    Console.WriteLine("{0} = ({1},{2:3X},{3:3X})",_c.K,_c.X.ToString("N3"),_c.Y.ToString("N3"),_c.Z.ToString("N3"));
                }
                break;
                
                case 'r':
                case 'R':
                var k1 = int.Parse(q[1]);
                
                Coord _c1 = d[k1];
                if(_c1==null||(lstB[0].Z<_c1.Z||_c1.Z<lstB[lstB.Count-1].Z))
                    {
                    Console.WriteLine("Point doesn't exist in the bucket.");
                }
                else
                    {
                    if(ptrC<lstC.Count)
                        {
                      //  lstB.Remove(_c1);
                        d[k1]=null;
                      //  remLst.Add(_c1.Z);
                        Console.WriteLine("Point id {0} removed.",k1);
                        lstB.Add(lstC[ptrC++]);
                        //lstB = lstB.OrderByDescending(x=>x.Z).ToList();
                      //  lstC.RemoveAt(0);
                    }
                    else
                        {                       
                    Console.WriteLine("No more points can be deleted.");
                }
                }
                break;
            }
            
            ipq =Console.ReadLine();
                
        }
        
        
    }
}

class Coord
    {
    public int K{get;set;}
    public double X{get;set;}
    public double Y{get;set;}
    public double Z{get;set;}
}