private static long Part2(params long[] buses)
{
return(buses
.Select((id, index) => new { id, index })
.Where(bus => bus.id != -1)
.Skip(1)
.Aggregate((value: buses[0], increment: buses[0]), (state, bus) => (
value: Produce.Forever(state.value, current => current + state.increment)
.First(current => (current + bus.index).IsMultipleOf(bus.id)),
increment: state.increment * bus.id
))
.value);
}
internal static long PlayCombat(Day22Input initialState)
{
var result = Produce.Forever(initialState,
state =>
{
var z = state.Player1.Zip(state.Player2).ToList();
var nextState = z.Aggregate((player1: state.Player1.Skip(z.Count).ToList(), player2: state.Player2.Skip(z.Count).ToList()), (accumulator, current) =>
{
current.First.Should().NotBe(current.Second);
if (current.First > current.Second)
{
accumulator.player1.AddRange(new [] { current.First, current.Second });
}
else
{
accumulator.player2.AddRange(new[] { current.Second, current.First });
}
return(accumulator);
});