/// <summary>
/// A set of numbered components are placed on a grid, a rover is placed on a random grid
/// coordinate and has to pick up the numbered components in ascending order(starting with 1).
/// Once the last component has been picked up the solution is complete.
/// </summary>
/// <returns>Returns a list of movements performed by the rover.</returns>
public IEnumerable <string> ProcessRover(RoverModel model)
{
var movementHistory = new List <string>();
foreach (RoverModel.Coordinate componentPosition in model.Components)
{
var availableCoords = GetAllCoords(model.GridSize, model.RoverPosition);
while (!model.RoverPosition.Equals(componentPosition)) // seek until landing on component
{
RoverModel.Coordinate nextMove = GetNextMove(model.RoverPosition, availableCoords, model.GridSize);
movementHistory.Add(SetDirection(nextMove, model.RoverPosition));
if (availableCoords.Contains(nextMove))
{
availableCoords.Remove(nextMove);
}
model.RoverPosition = nextMove;
}
// landed on component so add pickup to movement
movementHistory.Add("P");
}
return(movementHistory);
}
/// <summary>
/// Set direction the rover moved.
/// </summary>
private string SetDirection(RoverModel.Coordinate tempMove, RoverModel.Coordinate roverPosition)
{
string val = string.Empty;
if (tempMove.Latitude != roverPosition.Latitude)
{
if (tempMove.Latitude > roverPosition.Latitude)
{
val = "N";
}
else
{
val = "S";
}
}
else
{
if (tempMove.Longitude > roverPosition.Longitude)
{
val = "W";
}
else
{
val = "E";
}
}
return(val);
}
/// <summary>
/// Gets a list of all coordinates created based on grid size minus the rover position.
/// </summary>
private List <RoverModel.Coordinate> GetAllCoords(int gridSize, RoverModel.Coordinate roverPosition)
{
var list = new List <RoverModel.Coordinate>();
for (int i = 0; i < gridSize; i++)
{
for (int n = 0; n < gridSize; ++n)
{
list.Add(new RoverModel.Coordinate(i, n));
}
}
list.Remove(roverPosition);
return(list);
}
/// <summary>
/// Gets the rovers next cardinal movement coordinates.
/// </summary>
private RoverModel.Coordinate GetNextMove(RoverModel.Coordinate roverPosition, List <RoverModel.Coordinate> tempList, int gridSize)
{
RoverModel.Coordinate nextMove = new RoverModel.Coordinate(-1, -1);
RoverModel.Coordinate targetCoordinate = new RoverModel.Coordinate(-1, -1);
// seek out closest unused coordinate
var distanceList = new List <Tuple <int, RoverModel.Coordinate> >();
foreach (RoverModel.Coordinate coord in tempList)
{
int distance = Math.Abs((coord.Longitude - roverPosition.Longitude)) + Math.Abs((coord.Latitude - roverPosition.Latitude));
distanceList.Add(new Tuple <int, RoverModel.Coordinate>(distance, coord));
}
int closetDistance = gridSize * gridSize;
foreach (Tuple <int, RoverModel.Coordinate> t in distanceList)
{
if (t.Item1 < closetDistance)
{
closetDistance = t.Item1;
targetCoordinate = t.Item2;
}
}
// select next move towards targetCoordinate
if (targetCoordinate.Latitude > roverPosition.Latitude)
{
nextMove = new RoverModel.Coordinate(roverPosition.Longitude, roverPosition.Latitude + 1);
}
else if (targetCoordinate.Latitude < roverPosition.Latitude)
{
nextMove = new RoverModel.Coordinate(roverPosition.Longitude, roverPosition.Latitude - 1);
}
else if (targetCoordinate.Longitude > roverPosition.Longitude)
{
nextMove = new RoverModel.Coordinate(roverPosition.Longitude + 1, roverPosition.Latitude);
}
else if (targetCoordinate.Longitude < roverPosition.Longitude)
{
nextMove = new RoverModel.Coordinate(roverPosition.Longitude - 1, roverPosition.Latitude);
}
return(nextMove);
}
