private static long Part2(string input)
{
var cups = Parse(input);
var circle = new CupCircle(cups, 1000000);
Run(circle, 10000000);
var star1 = circle.Next(1);
var star2 = circle.Next(star1);
return((long)star1 * (long)star2);
}
private static void Run(CupCircle circle, int iterations)
{
var current = circle.Start;
for (int i = 0; i < iterations; i++)
{
var pickup1 = circle.Next(current);
var pickup2 = circle.Next(pickup1);
var pickup3 = circle.Next(pickup2);
var destination = current;
do
{
destination--;
if (destination == 0)
{
destination = circle.Max;
}
}while (destination == pickup1 || destination == pickup2 || destination == pickup3);
circle.Link(current, circle.Next(pickup3));
circle.Link(pickup3, circle.Next(destination));
circle.Link(destination, pickup1);
current = circle.Next(current);
}
}
