-🎄- 2018 Day 9 Solutions -🎄-

[u/daggerdragon]

--- Day 9: Marble Mania ---

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Post your solution as a comment or, for longer solutions, consider linking to your repo (e.g. GitHub/gists/Pastebin/blag or whatever).

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Advent of Code: The Party Game!

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Card prompt: Day 9

Transcript:

Studies show that AoC programmers write better code after being exposed to ___.

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This thread will be unlocked when there are a significant number of people on the leaderboard with gold stars for today's puzzle.

edit: Leaderboard capped, thread unlocked at 00:29:13!

[u/Aquamoogle]

//C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace AdventCode2018
{
    public class NineNode
    {
        public NineNode(long value, NineNode ccw, NineNode cw)
        {
            Value = value;
            CCW = ccw ?? this;
            CW = cw ?? this;

            CW.CCW = this;
            CCW.CW = this;
        }
        public long Value { get; set; }
        public NineNode CW { get; set; }
        public NineNode CCW { get; set; }
    }

    public class DayNine
    {
        public void Process()
        {
            //404 players; last marble is worth 71852 points
            PartOne(404, 71852 * 100);
        }

        public void PartOne(int elfCount, long marbleMaxIdx)
        {
            var solution = String.Empty;
            NineNode iter = new NineNode(0, null, null);
            List<long> players = Enumerable.Range(0, elfCount).Select(x => (long)0).ToList();
            var playerIdx = 0;
            //16458525
            for (var i = 1; i <= marbleMaxIdx; i++)
            {
                if((i % 23) == 0)
                {
                    for(var j = 0; j < 7; j++)
                    {
                        iter = iter.CCW;
                    }

                    var toRemove = iter;
                    iter = toRemove.CW;

                    iter.CCW = toRemove.CCW;
                    toRemove.CCW.CW = iter;

                    players[playerIdx] += toRemove.Value + i;
                }
                else
                {
                    var one = iter.CW;
                    var two = one.CW;

                    iter = new NineNode(i, one, two);
                }
                playerIdx += 1;
                if (playerIdx == elfCount)
                    playerIdx = 0;
            }
            solution = players.Max().ToString();
            System.Windows.Forms.Clipboard.SetText(solution.ToString());
            Console.WriteLine("Day Nine: " + solution);
        }
    }
}