private void OpenPoint(Point toOpen, State state, List <Point> notVisitedPoints, Dictionary <Point, DijkstraData> track)
{
for (var dy = -1; dy <= 1; dy++)
{
for (var dx = -1; dx <= 1; dx++)
{
if (dx == 0 || dy == 0)
{
var nextPoint = new Point(toOpen.X + dx, toOpen.Y + dy);
if (track.ContainsKey(nextPoint) || !state.InsideMap(nextPoint) || state.IsWallAt(nextPoint))
{
continue;
}
notVisitedPoints.Add(nextPoint);
var currentPrice = track[toOpen].Price + state.CellCost[nextPoint.X, nextPoint.Y];
if (!track.ContainsKey(nextPoint) || track[nextPoint].Price > currentPrice)
{
track[nextPoint] = new DijkstraData {
Previous = toOpen, Price = currentPrice
}
}
;
}
}
}
notVisitedPoints.Remove(toOpen);
}
}
public IEnumerable <PathWithCost> GetPathsByDijkstra(State state, Point start, IEnumerable <Point> targets)
{
HashSet <Point> chests = new HashSet <Point>(targets);
HashSet <Point> candidatesToOpen = new HashSet <Point>();
HashSet <Point> visitedNodes = new HashSet <Point>();
var track = new Dictionary <Point, DijkstraData>();
track[start] = new DijkstraData {
Price = 0, Previous = null
};
candidatesToOpen.Add(start);
while (true)
{
Point?toOpen = null;
var bestPrice = int.MaxValue;
foreach (var candidate in candidatesToOpen)
{
if (track[candidate].Price < bestPrice)
{
bestPrice = track[candidate].Price;
toOpen = candidate;
}
}
if (toOpen == null)
{
yield break;
}
if (chests.Contains(toOpen.Value))
{
yield return(MakePath(track, toOpen.Value));
}
var incidentNodes = GetIncidentNodes(toOpen.Value, state);
foreach (var incidentNode in incidentNodes)
{
var currentPrice = track[toOpen.Value].Price + state.CellCost[incidentNode.X, incidentNode.Y];
if (!track.ContainsKey(incidentNode) || track[incidentNode].Price > currentPrice)
{
track[incidentNode] = new DijkstraData {
Previous = toOpen, Price = currentPrice
};
}
if (!visitedNodes.Contains(incidentNode))
{
candidatesToOpen.Add(incidentNode);
}
}
candidatesToOpen.Remove(toOpen.Value);
visitedNodes.Add(toOpen.Value);
}
}
private static List <Node> Dijkstra(Graph graph, Dictionary <Edge, double> weights, Node start, Node end)
{
var notVisited = graph.Nodes.ToList();
var track = new Dictionary <Node, DijkstraData>();
track[start] = new DijkstraData {
Price = 0, Previous = null
};
while (true)
{
Node toOpen = null;
var bestPrice = double.PositiveInfinity;
foreach (var e in notVisited)
{
if (track.ContainsKey(e) && track[e].Price < bestPrice)
{
bestPrice = track[e].Price;
toOpen = e;
}
}
if (toOpen == null)
{
return(null);
}
if (toOpen == end)
{
break;
}
foreach (var e in toOpen.IncidentEdges.Where(z => z.From == toOpen))
{
var currentPrice = track[toOpen].Price + weights[e];
var nextNode = e.OtherNode(toOpen);
if (!track.ContainsKey(nextNode) || track[nextNode].Price > currentPrice)
{
track[nextNode] = new DijkstraData {
Previous = toOpen, Price = currentPrice
}
}
;
}
notVisited.Remove(toOpen);
}
var result = new List <Node>();
while (end != null)
{
result.Add(end);
end = track[end].Previous;
}
result.Reverse();
return(result);
}
private void WorkOnOpen(Point toOpen, State state, Dictionary <Point, DijkstraData> track)
{
foreach (var p in GetNextPoints(toOpen, state))
{
int currentPrice = state.CellCost[p.X, p.Y] + track[toOpen].Price;
if (!track.ContainsKey(p) || track[p].Price > currentPrice)
{
track[p] = new DijkstraData {
Previous = toOpen, Price = currentPrice
}
}
;
}
}
private DiscoveredData searchAllData(Point start, State state, List <Point> targets)
{
var pointValues = pointValuesInitialization(state, start);
var track = new Dictionary <Point, DijkstraData> {
[start] = new DijkstraData(start, 0, null)
};
var toOpenQueue = new Queue <DijkstraData>(new[] { track[start] });
var sortedTargets = new List <Point>();
while (toOpenQueue.Count != 0)
{
var toOpen = toOpenQueue.Dequeue();
foreach (var point in incidentPoints(toOpen.Point, state))
{
var value = state.CellCost[point.X, point.Y];
if (pointValues[point.X, point.Y] <= toOpen.Value + value || value == 0)
{
continue;
}
var currentPoint = new DijkstraData(point, value + toOpen.Value, toOpen);
if (!track.ContainsKey(currentPoint.Point))
{
track.Add(currentPoint.Point, currentPoint);
}
else
{
track[currentPoint.Point] = currentPoint;
}
toOpenQueue.Enqueue(currentPoint);
pointValues[point.X, point.Y] = value;
}
if (targets.Contains(toOpen.Point))
{
sortedTargets.Add(toOpen.Point);
}
toOpenQueue = new Queue <DijkstraData>(toOpenQueue.OrderBy(x => x.Value));
}
return(new DiscoveredData(track, sortedTargets));
}
private void GetNextPoint(State state, Dictionary <Point, DijkstraData> track, Point toOpen)
{
List <int> delta = new List <int>()
{
-1, 0, 1
};
var nextPointList = (from x in delta
from y in delta
where Math.Abs(x) != Math.Abs(y)
select new Point(toOpen.X + x, toOpen.Y + y))
.Where(point => state.InsideMap(point) && !state.IsWallAt(point)).ToList();
foreach (var point in nextPointList)
{
var currentPrice = track[toOpen].Price + state.CellCost[point.X, point.Y];
if (!track.ContainsKey(point) || track[point].Price > currentPrice)
{
track[point] = new DijkstraData {
Previous = toOpen, Price = currentPrice
};
}
}
}
private static void OpenCell(State state, Dictionary <Point, DijkstraData> track, Point cellToOpen)
{
var possibleDirections = new[]
{
new Point(-1, 0), new Point(0, -1),
new Point(0, 1), new Point(1, 0)
};
var nextCells = possibleDirections
.Select(point => new Point(point.X + cellToOpen.X, point.Y + cellToOpen.Y))
.Where(state.InsideMap)
.Where(point => !state.IsWallAt(point));
foreach (var cell in nextCells)
{
var currentPrice = track[cellToOpen].Price + state.CellCost[cell.X, cell.Y];
var nextPoint = cell;
if (!track.ContainsKey(nextPoint) || track[nextPoint].Price > currentPrice)
{
track[nextPoint] = new DijkstraData(cellToOpen, currentPrice);
}
}
}
public IEnumerable <PathWithCost> GetPathsByDijkstra(State state, Point start,
IEnumerable <Point> targets)
{
var notVisitedTargets = targets.ToList();
var notVisitedPoints = new List <Point>();
var track = new Dictionary <Point, DijkstraData>();
track[start] = new DijkstraData {
Previous = new Point(-1, -1), Price = 0
};
notVisitedPoints.Add(start);
while (notVisitedTargets.Any())
{
var path = GetPathByDijkstra(state, notVisitedPoints, track, notVisitedTargets);
if (path == null)
{
yield break;
}
yield return(path);
notVisitedTargets.Remove(path.End);
}
}
public IEnumerable <PathWithCost> GetPathsByDijkstra(State state, Point start,
IEnumerable <Point> targets)
{
var notVisited = GetMazePoints(state).Where(p => !state.IsWallAt(p)).ToList();
var track = new Dictionary <Point, DijkstraData>();
track[start] = new DijkstraData {
Price = 0, Previous = new Point(-1, -1)
};
while (true)
{
Point toOpen = GetPointToOpen(notVisited, track);
if (toOpen.X == -1)
{
yield break;
}
if (targets.Contains(toOpen))
{
yield return(GetPathFromTrack(track, toOpen));
}
WorkOnOpen(toOpen, state, track);
notVisited.Remove(toOpen);
}
}
public DijkstraData(Point point, int value, DijkstraData previous)
{
Point = point;
Value = value;
Previous = previous;
}