public ShuffleSequence(ShuffleSequence copyMe) : this(copyMe.DeckSize)
{
foreach (IShuffleAction action in copyMe.shuffleActions)
{
shuffleActions.Add(action.Copy());
}
}
public void AddToSequence(ShuffleSequence other)
{
List <IShuffleAction> newActions = new List <IShuffleAction>();
foreach (IShuffleAction action in other.shuffleActions)
{
newActions.Add(action.Copy());
}
shuffleActions.AddRange(newActions);
}
protected override void SolvePartTwo()
{
BigInteger deckSize = BigInteger.Parse("119315717514047");
BigInteger shuffleNtimes = BigInteger.Parse("101741582076661");
BigInteger findCard = 2020;
var shuffleSequence = new ShuffleSequence(shuffleMoves, deckSize);
shuffleSequence.CompressSequence();
var repeatedShuffles = SequenceAfterNRepetitions(shuffleSequence, shuffleNtimes);
resultPartTwo = repeatedShuffles.CardPositionBeforeShuffle(findCard).ToString();
}
public static ShuffleSequence SequenceAfterNRepetitions(ShuffleSequence shufSeq, BigInteger reps)
{
List <ShuffleSequence> shufflesPerBit = new List <ShuffleSequence> {
new ShuffleSequence(shufSeq)
};
int bitsNeeded = 0;
BigInteger previousBitValue = 1;
BigInteger bitValue = 2;
//Create shufflesequences for each bit value up to and including the largest bit value smaller than "reps"
while (bitValue < reps)
{
var next = new ShuffleSequence(shufflesPerBit[bitsNeeded]);
next.AddToSequence(next);
next.CompressSequence();
shufflesPerBit.Add(next);
previousBitValue = bitValue;
bitValue = previousBitValue * 2;
bitsNeeded++;
}
//Combine shufflesequences for each activated bit in the bit-representation of "reps"
var repeatedShuffleSequence = new ShuffleSequence(shufSeq.DeckSize);
BigInteger remaining = reps;
for (int i = shufflesPerBit.Count - 1; i >= 0; i--)
{
if (previousBitValue <= remaining)
{
repeatedShuffleSequence.AddToSequence(shufflesPerBit[i]);
repeatedShuffleSequence.CompressSequence();
remaining = remaining - previousBitValue;
}
previousBitValue = previousBitValue / 2;
}
return(repeatedShuffleSequence);
}
protected override void SolvePartOne()
{
var shuffleSequence = new ShuffleSequence(shuffleMoves, 10007);
resultPartOne = shuffleSequence.CardPositionAfterShuffle(2019).ToString();
}