private static Cup ProcessInput(string input, int cupCount)
{
cupLookup = new Dictionary <int, Cup>();
Cup firstCup = new Cup(input[0] - '0', null);
cupLookup.Add(firstCup.CupLabel, firstCup);
Cup newCup = firstCup;
for (int i = 1; i < cupCount; i++)
{
if (i < input.Length)
{
newCup = new Cup(input[i] - '0', newCup);
cupLookup.Add(newCup.CupLabel, newCup);
maxCup = Math.Max(maxCup, input[i] - '0');
}
else
{
newCup = new Cup(i + 1, newCup);
cupLookup.Add(newCup.CupLabel, newCup);
maxCup = i + 1;
}
}
firstCup.PreviousCup = newCup;
newCup.NextCup = firstCup;
return(firstCup);
}
public Cup(int label, Cup previous)
{
this.cupLabel = label;
this.previousCup = previous;
if (previous != null)
{
previous.NextCup = this;
}
}
public static string B(string input)
{
Cup firstCup = ProcessInput(input, 1000000);
for (int i = 0; i < 10000000; i++)
{
firstCup = PlayRound(firstCup);
}
// find the 1
Cup currentCup = cupLookup[1];
return(((long)currentCup.NextCup.CupLabel * (long)currentCup.NextCup.NextCup.CupLabel).ToString());
}
private static Cup PlayRound(Cup firstCup)
{
Cup currentCup = firstCup;
Cup startRemove = currentCup.NextCup;
Cup endRemove = startRemove.NextCup.NextCup;
int labelToFind = currentCup.CupLabel - 1;
if (labelToFind < 1)
{
labelToFind = maxCup;
}
while (labelToFind == startRemove.CupLabel || labelToFind == startRemove.NextCup.CupLabel || labelToFind == endRemove.CupLabel)
{
labelToFind--;
if (labelToFind < 1)
{
labelToFind = maxCup;
}
}
Cup destinationCup = cupLookup[labelToFind];
Cup newFirstCup = endRemove.NextCup;
// fix the new loop, removing the removed cups
newFirstCup.PreviousCup = firstCup;
firstCup.NextCup = newFirstCup;
// insert the removed Cups
Cup postDestinationCup = destinationCup.NextCup;
destinationCup.NextCup = startRemove;
startRemove.PreviousCup = destinationCup;
endRemove.NextCup = postDestinationCup;
postDestinationCup.PreviousCup = endRemove;
return(newFirstCup);
}
public static string A(string input)
{
Cup firstCup = ProcessInput(input, 9);
for (int i = 0; i < 100; i++)
{
firstCup = PlayRound(firstCup);
}
// find the 1
Cup currentCup = cupLookup[1];
StringBuilder returnString = new StringBuilder();
do
{
currentCup = currentCup.NextCup;
returnString.Append(currentCup.CupLabel);
} while (currentCup.CupLabel != 1);
returnString.Remove(returnString.Length - 1, 1);
return(returnString.ToString());
}