Advent2019/Day7/Day7.cs

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

namespace Advent
{
    public static class Day7
    {
        public static void Execute()
        {
            var program = "3,8,1001,8,10,8,105,1,0,0,21,34,43,64,85,98,179,260,341,422,99999,3,9,1001,9,3,9,102,3,9,9,4,9,99,3,9,102,5,9,9,4,9,99,3,9,1001,9,2,9,1002,9,4,9,1001,9,3,9,1002,9,4,9,4,9,99,3,9,1001,9,3,9,102,3,9,9,101,4,9,9,102,3,9,9,4,9,99,3,9,101,2,9,9,1002,9,3,9,4,9,99,3,9,101,1,9,9,4,9,3,9,1002,9,2,9,4,9,3,9,102,2,9,9,4,9,3,9,102,2,9,9,4,9,3,9,102,2,9,9,4,9,3,9,102,2,9,9,4,9,3,9,1001,9,1,9,4,9,3,9,1001,9,1,9,4,9,3,9,101,2,9,9,4,9,3,9,1001,9,2,9,4,9,99,3,9,101,1,9,9,4,9,3,9,102,2,9,9,4,9,3,9,101,2,9,9,4,9,3,9,1001,9,1,9,4,9,3,9,1002,9,2,9,4,9,3,9,102,2,9,9,4,9,3,9,1002,9,2,9,4,9,3,9,101,1,9,9,4,9,3,9,102,2,9,9,4,9,3,9,1002,9,2,9,4,9,99,3,9,101,1,9,9,4,9,3,9,1002,9,2,9,4,9,3,9,102,2,9,9,4,9,3,9,1001,9,2,9,4,9,3,9,1001,9,1,9,4,9,3,9,101,1,9,9,4,9,3,9,1002,9,2,9,4,9,3,9,1001,9,2,9,4,9,3,9,101,1,9,9,4,9,3,9,101,1,9,9,4,9,99,3,9,101,1,9,9,4,9,3,9,1001,9,1,9,4,9,3,9,102,2,9,9,4,9,3,9,1001,9,1,9,4,9,3,9,102,2,9,9,4,9,3,9,1001,9,2,9,4,9,3,9,102,2,9,9,4,9,3,9,101,1,9,9,4,9,3,9,1001,9,2,9,4,9,3,9,1002,9,2,9,4,9,99,3,9,101,2,9,9,4,9,3,9,101,2,9,9,4,9,3,9,1002,9,2,9,4,9,3,9,102,2,9,9,4,9,3,9,101,2,9,9,4,9,3,9,102,2,9,9,4,9,3,9,1001,9,2,9,4,9,3,9,1002,9,2,9,4,9,3,9,1001,9,1,9,4,9,3,9,102,2,9,9,4,9,99";

            var phaseList = GetPhaseList();

            int? max = 0;

            var amp = new IntcodeComputer();

            foreach (var phases in phaseList)
            {
                var output = amp.Execute(new[] { phases[0], 0 }, program);
                output = amp.Execute(new[] { phases[1], output.GetValueOrDefault(0) }, program);
                output = amp.Execute(new[] { phases[2], output.GetValueOrDefault(0) }, program);
                output = amp.Execute(new[] { phases[3], output.GetValueOrDefault(0) }, program);
                output = amp.Execute(new[] { phases[4], output.GetValueOrDefault(0) }, program);

                if (output > max)
                    max = output;
            }

            Console.WriteLine(max);
        }

        private static IEnumerable<int[]> GetPhaseList()
        {
            // This is a stupid brute force way to do it but I'm lazy and it is fast so good enough

            var phaseList = new List<int[]>();

            for (var i = 0; i <= 99999; i++)
            {
                var phases = i.ToString("00000").ToCharArray().Select(c => int.Parse(c.ToString())).ToArray();

                if (phases.All(p => p <= 4) && phases.Distinct().Count() == 5)
                    phaseList.Add(phases);
            }

            return phaseList;
        }
    }
}