public static IEnumerable <AoCPoint> Adjacent(this AoCPoint point, bool diagonal)
{
if (diagonal)
{
yield return(point.Up().Left());
}
yield return(point.Up());
if (diagonal)
{
yield return(point.Up().Right());
}
yield return(point.Right());
if (diagonal)
{
yield return(point.Down().Right());
}
yield return(point.Down());
if (diagonal)
{
yield return(point.Down().Left());
}
yield return(point.Left());
}
public static IEnumerable <AoCPoint> Adjacent(this AoCPoint point)
{
yield return(point.Up());
yield return(point.Right());
yield return(point.Down());
yield return(point.Left());
}