public override void PartOne(IInput input, IOutput output)
{
var current = Point2d.Origin;
var direction = Direction.North;
foreach (var directions in input.Parse())
{
direction = directions.Direction switch
{
'L' => direction.Left(),
'R' => direction.Right(),
_ => throw new InvalidOperationException("Invalid direction")
};
current = Point2d.AddInDirection(current, direction, directions.Distance);
}
var distance = PointHelpers.ManhattanDistance(Point2d.Origin, current);
output.WriteProperty("Distance from start in blocks", distance);
}
private static int CountActiveNeighbours(Point2d point, ImmutableHashSet <Point2d> bugs)
{
var count = 0;
var adjacent = new[]
{
Point2d.AddInDirection(point, Direction.North, 1),
Point2d.AddInDirection(point, Direction.East, 1),
Point2d.AddInDirection(point, Direction.South, 1),
Point2d.AddInDirection(point, Direction.West, 1),
};
foreach (var neighbour in adjacent)
{
if (bugs.Contains(neighbour))
{
count++;
}
}
return(count);
}