linear 6

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

//Write a program that removes from given sequence all numbers that occur odd number of times.

class Task5
{
    static void Main()
    {
        Console.WriteLine("Enter some integers separated by space.For end hit \"return\"");
        LinkedList<int> list = AddingToList(Console.ReadLine());
        list = RemoveOdds(list);
        Console.WriteLine(string.Join(" ", list));
    }

    private static LinkedList<int> RemoveOdds(LinkedList<int> list)
    {
        Dictionary<int,int> counter = new Dictionary<int,int>();
        foreach (int item in list)
        {
            if (counter.Keys.Contains(item))
            {
                counter[item]++;
                continue;
            }
            counter.Add(item,1);
        }

    var node = list.First;
        while (node != null)
        {
            var next = node.Next;
            if (counter[node.Value] % 2 != 0)
            {
                list.Remove(node);
            }
            node = next;
        }
        return list;
    }

    public static LinkedList<int> AddingToList(string input)
    {
        LinkedList<int> result = new LinkedList<int>();
        string[] strList = input.Split(' ');
        foreach (string item in strList) result.AddLast(int.Parse(item));
        return result;
    }
}