using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        var test = new List<int> { -2, 4, -1, 3, -5, 10, 4, -2, 1, -5, -5, -5};

        var test2 = RemoveAll(test, x => x < 0);

        Console.WriteLine(string.Join(" ", test));

        Console.WriteLine(string.Join(" ", test2));

    }

    public static List<T> RemoveAll<T>(List<T> input, Func<T,bool> condition)

    {

    List<T> removedEntries = new List<T>();

    int offset = 0;

    for(int i = 0; i < input.Count - offset; i++)

    {

      while(i < input.Count - offset && condition.Invoke(input[i + offset]))

      {

         removedEntries.Add(input[i + offset]);

         offset++; 

         Console.WriteLine("i="+i+", offset="+offset);

      }

      if(i < input.Count - offset)

      {

          input[i] = input[i+offset];

      }

    }

    input.RemoveRange(input.Count - offset, offset);

    return removedEntries;

    }

}