private void IsValidPath(Map map, MoveDirection[] path, int expectedPathLength)
{
var chestTaken = false;
var chestSet = new HashSet <Point>(map.Chests);
var walker = new Walker(map.InitialPosition);
foreach (var step in path)
{
walker = walker.WalkInDirection(map, step);
if (walker.PointOfCollision.HasValue)
{
Assert.Fail($"Collided with wall at {walker.PointOfCollision.Value}");
}
if (chestSet.Contains(walker.Position))
{
chestTaken = true;
}
}
Assert.True(chestTaken, "Player did not take any chest.");
Assert.AreEqual(map.Exit, walker.Position, "Player did not reach the exit.");
Assert.GreaterOrEqual(path.Length, expectedPathLength,
"Hmm.... Seems to be an error in the checker. Please notify us in the comments below.");
Assert.AreEqual(expectedPathLength, path.Length, "Path must be shortest.");
}
public static IEnumerable <SinglyLinkedList <Point> > FindPaths(Map map, Point start, Point[] chests)
{
var queue = new Queue <SinglyLinkedList <Point> >();
var roads = new HashSet <Point> {
start
};
var hashChests = chests.ToHashSet();
var directions = new[] { 0, 1, 2, 3 };
queue.Enqueue(new SinglyLinkedList <Point>(start));
while (queue.Count != 0)
{
var currentPath = queue.Dequeue();
var walker = new Walker(currentPath.Value);
foreach (var newPosition in
directions
.Select(x => walker.WalkInDirection(map, (MoveDirection)x))
.Where(x => x.PointOfCollision == null && !roads.Contains(x.Position))
.Select(x => x.Position))
{
var path = new SinglyLinkedList <Point>(newPosition, currentPath);
queue.Enqueue(path);
roads.Add(newPosition);
if (hashChests.Contains(newPosition))
{
yield return(path);
}
}
}
}
public static IEnumerable <SinglyLinkedList <Point> > FindPaths(Map map, Point start, Point[] chests)
{
var queue = new Queue <SinglyLinkedList <Point> >();
var visited = new HashSet <Point> {
start
};
var chestsHashSet = chests.ToHashSet();
queue.Enqueue(new SinglyLinkedList <Point>(start));
while (queue.Count != 0)
{
var currentPosition = queue.Dequeue();
var walker = new Walker(currentPosition.Value);
var nextPositions = directions
.Select(direction => walker.WalkInDirection(map, direction))
.Where(w => w.PointOfCollision == null && !visited.Contains(w.Position))
.Select(w => w.Position);
foreach (var nextPosition in nextPositions)
{
var nextPath = new SinglyLinkedList <Point>(nextPosition, currentPosition);
queue.Enqueue(nextPath);
visited.Add(nextPosition);
if (chestsHashSet.Contains(nextPosition))
{
yield return(nextPath);
}
}
}
}
private IEnumerable <Point> TransformPath(Map map, MoveDirection[] path)
{
var walker = new Walker(map.InitialPosition);
yield return(map.InitialPosition);
foreach (var direction in path)
{
walker = walker.WalkInDirection(map, direction);
yield return(walker.Position);
if (walker.PointOfCollision.HasValue)
{
break;
}
}
}