using System;

using System.Collections.Generic;

​

public class Solution

{

    public static bool CanTwoMoviesFillFlight(int[] movieLengths, int flightLength)

    {

        // Determine if two movies add up to the flight length

        HashSet<int> movieLengthsSeen = new HashSet<int>();

        foreach(int movieLength in movieLengths)

        {

            if(movieLengthsSeen.Contains(flightLength - movieLength))

            {

                return true;

            }

            movieLengthsSeen.Add(movieLength);

        }

        return false;

    }

​

    // Tests

    public void Main()

    {

        //short flight test

        var result = CanTwoMoviesFillFlight(new int[] { 2, 4 }, 1);

        Console.WriteLine(result == false);

        //long flight test

        result = CanTwoMoviesFillFlight(new int[] { 2, 4 }, 6);

        Console.WriteLine(result == true);

        //only one movie half flight length test

        result = CanTwoMoviesFillFlight(new int[] { 3, 8 }, 6);

        Console.WriteLine(result == false);     

        //Two movies half flight length test

        result = CanTwoMoviesFillFlight(new int[] { 3, 8, 3 }, 6);

        Console.WriteLine(result == true);

        //Lots of possible pairs test

        result = CanTwoMoviesFillFlight(new int[] { 1, 2, 3, 4, 5, 6 }, 7);

        Console.WriteLine(result == true);

        //Not using first movie test

        result = CanTwoMoviesFillFlight(new int[] { 4, 3, 2 }, 5);

        Console.WriteLine(result == true);

        //one movie test

        result = CanTwoMoviesFillFlight(new int[] { 6 }, 6);

        Console.WriteLine(result == false);

        //no movie test

        result = CanTwoMoviesFillFlight(new int[] { }, 6);

        Console.WriteLine(result == false);

    }

}