public bool DecksMatch(Decks decks)
{
var matched = true;
if (decks.Player1.Count != Player1.Count || decks.Player2.Count != Player2.Count)
{
return(false);
}
for (var i = 0; i < Player1.Count; i++)
{
if (decks.Player1[i] != Player1[i])
{
matched = false;
break;
}
}
for (var i = 0; i < Player2.Count; i++)
{
if (decks.Player2[i] != Player2[i])
{
matched = false;
break;
}
}
return(matched);
}
private void PlayPart1Round(Decks decks)
{
var player1Card = decks.Player1.Last();
var player2Card = decks.Player2.Last();
decks.Player1.Remove(player1Card);
decks.Player2.Remove(player2Card);
if (player1Card > player2Card)
{
decks.Player1 = decks.Player1.Prepend(player1Card).Prepend(player2Card).ToList();
}
else
{
decks.Player2 = decks.Player2.Prepend(player2Card).Prepend(player1Card).ToList();
}
}
private long PlayPart1(Decks decks)
{
while (decks.Player1.Count > 0 && decks.Player2.Count > 0)
{
PlayPart1Round(decks);
}
var score = 0L;
var winningDeck = decks.Player1.Count > 0 ? decks.Player1 : decks.Player2;
var index = 0;
foreach (var card in winningDeck)
{
index++;
score += index * card;
}
return(score);
}
private long PlayPart2(Decks decks)
{
var storedSubDecks = new List <Decks>();
while (decks.Player1.Count > 0 && decks.Player2.Count > 0)
{
PlayPart2Round(decks, storedSubDecks, 1);
}
var score = 0L;
var winningDeck = decks.Player1.Count > 0 ? decks.Player1 : decks.Player2;
var index = 0;
foreach (var card in winningDeck)
{
index++;
score += index * card;
}
return(score);
}
protected override void DoSolve(string input)
{
var decksPart1 = new Decks();
var decksPart2 = new Decks();
var inputs = input.SplitByLine();
inputs.Reverse(0, inputs.Count);
var nextPlayer = true;
foreach (var line in inputs)
{
if (line.StartsWith("Player 2"))
{
nextPlayer = false;
continue;
}
if (int.TryParse(line, out var num))
{
if (nextPlayer)
{
decksPart1.Player2.Add(num);
decksPart2.Player2.Add(num);
}
else
{
decksPart1.Player1.Add(num);
decksPart2.Player1.Add(num);
}
}
}
var part1Count = PlayPart1(decksPart1);
var part2Count = PlayPart2(decksPart2);
PartOneAnswer = part1Count.ToString();
PartTwoAnswer = part2Count.ToString();
}
private bool PlayPart2Round(Decks decks, List <Decks> storedDecks, int game)
{
var player1Card = decks.Player1.Last();
var player2Card = decks.Player2.Last();
foreach (var storedDeck in storedDecks)
{
if (storedDeck.DecksMatch(decks))
{
return(true);
}
}
storedDecks.Add(decks.DeepCopy(decks.Player1.Count, decks.Player2.Count));
//Console.WriteLine($"-- Game {game} --");
//Console.WriteLine($"Player 1: {player1Card} ({string.Join(", ", decks.Player1)})");
//Console.WriteLine($"Player 2: {player2Card} ({string.Join(", ", decks.Player2)})");
//Console.WriteLine("---- END -----");
decks.Player1.Remove(player1Card);
decks.Player2.Remove(player2Card);
if (player1Card <= decks.Player1.Count && player2Card <= decks.Player2.Count)
{
// if value of card is less or equal to remaining card count
// do recursive game. Copy cards and then recurse.
var subDecks = decks.DeepCopy(player1Card, player2Card);
var storedSubDecks = new List <Decks>();
var terminated = false;
while (subDecks.Player1.Count > 0 && subDecks.Player2.Count > 0)
{
terminated = PlayPart2Round(subDecks, storedSubDecks, game + 1);
if (terminated)
{
break;
}
}
if (terminated || subDecks.Player1.Count > 0)
{
decks.Player1 = decks.Player1.Prepend(player1Card).Prepend(player2Card).ToList();
}
else
{
decks.Player2 = decks.Player2.Prepend(player2Card).Prepend(player1Card).ToList();
}
}
else
{
// else, use rules as of part 1.
if (player1Card > player2Card)
{
decks.Player1 = decks.Player1.Prepend(player1Card).Prepend(player2Card).ToList();
}
else
{
decks.Player2 = decks.Player2.Prepend(player2Card).Prepend(player1Card).ToList();
}
}
return(false);
}