public string Run(Aoc.Framework.Part part)
{
if (part == Aoc.Framework.Part.Part1)
{
// Prepare the data
Queue <(long, long)> queue = new Queue <(long, long)>();
for (int i = 0; i < _count; ++i)
{
queue.Enqueue((i + 1, 1));
}
// Process the queue
while (queue.TryDequeue(out var elf))
{
if (!queue.TryDequeue(out var next))
{
// The elf is the last one, he won
return(elf.Item1.ToString());
}
// Steal the presents !
queue.Enqueue((elf.Item1, elf.Item2 + next.Item2));
}
return("not found");
}
if (part == Aoc.Framework.Part.Part2)
{
// The same with another structure
SparseArray <long> elves = new SparseArray <long>(_count);
for (long i = 0; i < elves.Length; ++i)
{
elves[i] = 1;
}
// Process the array
long current = 0;
long opposite = elves.RealLength / 2;
while (elves.RealLength > 1)
{
elves[current] += elves[opposite];
elves.RemoveAt(opposite);
if (elves.RealLength % 2 == 0)
{
opposite = elves.Next(opposite, 2);
}
else
{
opposite = elves.Next(opposite, 1);
}
current = elves.Next(current);
}
return((current + 1).ToString());
}
return("");
}