private static Grid.Point GetClosestVertex(List <Grid.Point> list, Dictionary <Grid.Point, float> distanceMap)
{
Grid.Point candidate = list[0];
foreach (Grid.Point vertex in list)
{
if (distanceMap[vertex] < distanceMap[candidate])
{
candidate = vertex;
}
}
return(candidate);
}
public static List <Grid.Point> GeneratePath(Dictionary <Grid.Point, Grid.Point> parentMap, Grid.Point endState)
{
List <Grid.Point> path = new List <Grid.Point>();
Grid.Point parent = endState;
while (parent != null && parentMap.ContainsKey(parent))
{
path.Add(parent);
parent = parentMap[parent];
}
return(path);
}
public static List <Grid.Point> Dijkstra(Grid grid, Grid.Point startPos, Grid.Point endPos)
{
List <Grid.Point> unfinishedVertices = new List <Grid.Point>();
Dictionary <Grid.Point, float> distanceMap = new Dictionary <Grid.Point, float>();
Dictionary <Grid.Point, Grid.Point> visitedMap = new Dictionary <Grid.Point, Grid.Point>();
unfinishedVertices.Add(startPos);
distanceMap.Add(startPos, 0);
visitedMap.Add(startPos, null);
while (unfinishedVertices.Count > 0)
{
Grid.Point vertex = GetClosestVertex(unfinishedVertices, distanceMap);
unfinishedVertices.Remove(vertex);
if (vertex.Equals(endPos))
{
return(GeneratePath(visitedMap, vertex));
}
foreach (Grid.Point adj in grid.GetAdjacentCells(vertex))
{
if (!visitedMap.ContainsKey(adj))
{
unfinishedVertices.Add(adj);
}
float adjDist = distanceMap.ContainsKey(adj) ? distanceMap[adj] : int.MaxValue;
float vDist = distanceMap.ContainsKey(vertex) ? distanceMap[vertex] : int.MaxValue;
if (adjDist > vDist + grid.GetCostOfEnteringCell(adj))
{
if (distanceMap.ContainsKey(adj))
{
distanceMap[adj] = vDist + grid.GetCostOfEnteringCell(adj);
}
else
{
distanceMap.Add(adj, vDist + grid.GetCostOfEnteringCell(adj));
}
if (visitedMap.ContainsKey(adj))
{
visitedMap[adj] = vertex;
}
else
{
visitedMap.Add(adj, vertex);
}
}
}
}
return(null);
}
public static List <Grid.Point> BreadthFirstSearch(Grid grid, Grid.Point startPos, Grid.Point endPos)
{
if (startPos.Equals(endPos))
{
return(new List <Grid.Point>()
{
startPos
});
}
Dictionary <Grid.Point, Grid.Point> visitedMap = new Dictionary <Grid.Point, Grid.Point>();
Queue <Grid.Point> queue = new Queue <Grid.Point>();
queue.Enqueue(startPos);
while (queue.Count > 0)
{
Grid.Point node = queue.Dequeue();
foreach (Grid.Point adj in grid.GetAdjacentCells(node))
{
if (!visitedMap.ContainsKey(adj))
{
visitedMap.Add(adj, node);
queue.Enqueue(adj);
if (adj.Equals(endPos))
{
return(GeneratePath(visitedMap, adj));
}
}
}
if (!visitedMap.ContainsKey(node))
{
visitedMap.Add(node, null);
}
}
return(null);
}
public static List <Grid.Point> DepthFirstSearch(Grid grid, Grid.Point startPos, Grid.Point endPos)
{
if (startPos.Equals(endPos))
{
return(new List <Grid.Point>()
{
startPos
});
}
Dictionary <Grid.Point, Grid.Point> visitedMap = new Dictionary <Grid.Point, Grid.Point>();
Stack <Grid.Point> stack = new Stack <Grid.Point>();
stack.Push(startPos);
while (stack.Count > 0)
{
Grid.Point node = stack.Pop();
foreach (Grid.Point adj in grid.GetAdjacentCells(node))
{
if (!visitedMap.ContainsKey(adj))
{
visitedMap.Add(adj, node);
stack.Push(adj);
if (adj.Equals(endPos))
{
return(GeneratePath(visitedMap, adj));
}
}
}
if (!visitedMap.ContainsKey(node))
{
visitedMap.Add(node, null);
}
}
return(null);
}
