private IEnumerable <SeatNeighborhood> GetImmediateSeatNeighborhoods(SeatsMap sm)
{
List <SeatNeighborhood> neighborhoods = new List <SeatNeighborhood>();
foreach (Tuple <int, int> seat in sm.Seats)
{
// Unrolling the cases for all eight directions.
SeatNeighborhood sn = new SeatNeighborhood(seat);
Tuple <int, int> candidate = Tuple.Create(seat.Item1 - 1, seat.Item2 - 1);
if (sm.ContainsKey(candidate))
{
sn.SetNeighbor(Direction.TopLeft, candidate);
}
candidate = Tuple.Create(seat.Item1 - 1, seat.Item2);
if (sm.ContainsKey(candidate))
{
sn.SetNeighbor(Direction.Top, candidate);
}
candidate = Tuple.Create(seat.Item1 - 1, seat.Item2 + 1);
if (sm.ContainsKey(candidate))
{
sn.SetNeighbor(Direction.TopRight, candidate);
}
candidate = Tuple.Create(seat.Item1, seat.Item2 + 1);
if (sm.ContainsKey(candidate))
{
sn.SetNeighbor(Direction.Right, candidate);
}
candidate = Tuple.Create(seat.Item1 + 1, seat.Item2 + 1);
if (sm.ContainsKey(candidate))
{
sn.SetNeighbor(Direction.BottomRight, candidate);
}
candidate = Tuple.Create(seat.Item1 + 1, seat.Item2);
if (sm.ContainsKey(candidate))
{
sn.SetNeighbor(Direction.Bottom, candidate);
}
candidate = Tuple.Create(seat.Item1 + 1, seat.Item2 - 1);
if (sm.ContainsKey(candidate))
{
sn.SetNeighbor(Direction.BottomLeft, candidate);
}
candidate = Tuple.Create(seat.Item1, seat.Item2 - 1);
if (sm.ContainsKey(candidate))
{
sn.SetNeighbor(Direction.Left, candidate);
}
yield return(sn);
}
}
private void Stabilize
(SeatsMap sm
, Func <SeatsMap, IEnumerable <SeatNeighborhood> > getNeighborhoods
, int maxUsedNeighbors)
{
bool iterate = true;
List <SeatNeighborhood> neighborhoods = getNeighborhoods(sm).ToList();
while (iterate)
{
var modifications = GetModifications(sm, neighborhoods, maxUsedNeighbors).ToList();
iterate = modifications.Any();
foreach (var tuple in modifications)
{
sm[tuple.Item1] = tuple.Item2;
}
}
}
private IEnumerable <Tuple <Tuple <int, int>, char> > GetModifications
(SeatsMap sm
, IEnumerable <SeatNeighborhood> neighborhoods
, int maxUsedNeighbors)
{
foreach (SeatNeighborhood sn in neighborhoods)
{
switch (sm[sn.Seat])
{
case FreeSeat when sn.Neighbors.All(seat => sm[seat] == FreeSeat):
yield return(Tuple.Create(sn.Seat, UsedSeat));
break;
case UsedSeat when sn.Neighbors.Count(seat => sm[seat] == UsedSeat) >= maxUsedNeighbors:
yield return(Tuple.Create(sn.Seat, FreeSeat));
break;
}
}
}
private SeatsMap GetSeatsMap(IEnumerable <string> input)
{
SeatsMap sm = new SeatsMap();
int row = 0;
foreach (var line in input)
{
int col = 0;
foreach (var c in line)
{
if (c == FreeSeat)
{
sm[row, col] = c;
}
col++;
}
row++;
}
return(sm);
}
private IEnumerable <SeatNeighborhood> GetClosestSeatNeighborhoods(SeatsMap sm)
{
List <SeatNeighborhood> neighborhoods = new List <SeatNeighborhood>();
foreach (Tuple <int, int> seat in sm.Seats)
{
SeatNeighborhood sn = new SeatNeighborhood(seat);
foreach (SeatNeighborhood neighborhood in neighborhoods)
{
if (TryGetDirection(neighborhood.Seat, seat, out var direction))
{
Direction opposite = GetOppositeDirection(direction);
Tuple <int, int> neighbor = neighborhood.GetNeighbor(direction);
if (neighbor is Tuple <int, int> )
{
int neighborDist = GetManhattanDistance(neighbor, neighborhood.Seat);
int seatDist = GetManhattanDistance(seat, neighborhood.Seat);
if (seatDist < neighborDist)
{
neighborhood.SetNeighbor(direction, seat);
sn.SetNeighbor(opposite, neighborhood.Seat);
}
}
else
{
neighborhood.SetNeighbor(direction, seat);
sn.SetNeighbor(opposite, neighborhood.Seat);
}
}
}
neighborhoods.Add(sn);
}
return(neighborhoods);
}
