/// <summary>
/// 计算图中自环的个数（自环就是边连到自己形成的环）
/// </summary>
/// <returns>自环的个数</returns>
public static int SelfLoopCount(this IGraph graph)
{
int cnt = 0;
for (int vertex = 0; vertex < graph.VertexCount; vertex++)
{
cnt += graph.Adjacent(vertex).Count(v => v == vertex);
}
return(cnt / 2); // 每条边都会被计算两次，所以要除以2
}
private void SearchC(int v)
{
order[v] = counter++;
foreach (int adj in g.Adjacent(v))
{
if (order[adj] == -1)
{
SearchC(adj);
}
}
}
public List <IVertex> GetWay()
{
Open = new PriorityQueue();
Close = new List <IVertex>();
var s = new List <IVertex>();
s.Add(start);
Open.Add(FFunction(s), s);
while (Open.Count != 0)
{
// Выбираем наилучший путь из очереди
var p = Open.First();
Open.RemoveFirst();
// Рассматриваем его последнюю вершину
var x = p.Last();
// Если она уже была посещена, отбрасываем этот путь
if (Close.Contains(x))
{
continue;
}
// Если это целевая вершина, сохраним стоимость пути и вернем его
if (x.Equals(goal))
{
currentPathLength = 0;
for (int i = 1; i < p.Count; i++)
{
currentPathLength += graph.Cost(p[i], p[i - 1]);
}
firstRun = false;
return(p);
}
// Отмечаем текущую вершину как посещенную
Close.Add(x);
// Раскрываем непосещенные смежные вершины
foreach (var y in graph.Adjacent(x))
{
if (!Close.Contains(y))
{
var newPath = new List <IVertex>(p);
newPath.Add(y);
// Если это первый запуск, то алгоритм работает, как стандартный алгоритм А*
// Иначе отбрасываем потенциальные пути, для которых допустимая функция дает оценку, большую, чем стоимость последнего найденного пути
if (firstRun || FAccessibleFunction(newPath) < currentPathLength)
{
Open.Add(FFunction(newPath), newPath);
}
}
}
}
// Если путь не нашелся, выбрасываем исключение
throw new Exception();
}
private void DFS(IGraph graph, int vertex)
{
isConnected[vertex] = true;
foreach (var v in graph.Adjacent(vertex))
{
if (!isConnected[v])
{
edgeTo[v] = vertex;
DFS(graph, v);
}
}
}
private void DFS(IGraph g, int v)
{
_marked[v] = true;
_id[v] = Count;
foreach (var w in g.Adjacent(v))
{
if (!_marked[w])
{
DFS(g, w);
}
}
}
private void DFS(IGraph graph, int vertex)
{
isConnected[vertex] = true;
id[vertex] = count;
foreach (var v in graph.Adjacent(vertex))
{
if (!isConnected[v])
{
DFS(graph, v);
}
}
}
protected virtual void DFS(IGraph graph, int vertex)
{
isConnected[vertex] = true;
count++;
foreach (var v in graph.Adjacent(vertex))
{
if (!isConnected[v])
{
DFS(graph, v);
}
}
}
public UnionFindSearch(IGraph graph, int vertex)
{
vertexCount = graph.VertexCount;
uf = new UnionFind(vertexCount);
start = vertex;
for (int from = 0; from < vertexCount; from++)
{
foreach (int to in graph.Adjacent(from))
{
uf.Union(from, to);
}
}
}
public void AdjacentTest()
{
IGraph <int> graph = GraphMap.New <int>();
for (int i = 1; i <= 5; i++)
{
graph.Add(i);
}
graph.Add(1, 5);
graph.Add(2, 5);
graph.Add(3, 5);
graph.Add(4, 5);
Assert.IsTrue(graph.Adjacent(1, 5));
}
/// <summary>
/// 在控制台打印出图的顶点以及边的信息
/// </summary>
public static void Print(this IGraph graph)
{
Console.WriteLine("打印图");
Console.WriteLine(graph.VertexCount + "个顶点 " + graph.EdgeCount + "条边");
for (int i = 0; i < graph.EdgeCount; i++)
{
Console.Write(i + ": ");
foreach (var vertex in graph.Adjacent(i))
{
Console.Write(vertex + " ");
}
Console.WriteLine();
}
}
// Pathfinding
public List <Vector3> GetWay()
{
Open = new PriorityQueue();
Close = new List <IVertex>();
var s = new List <IVertex>();
s.Add(start);
Open.Add(FFunction(s), s);
while (Open.Count != 0)
{
if (CheckForCancellationRequested())
{
return(null);
}
var p = Open.First();
Open.RemoveFirst();
var x = p.Last();
if (Close.Contains(x))
{
continue;
}
if (x.Equals(goal))
{
spaceManagerInstance.pathfindingThreadsCurCount--;
return(p.Select(el => SpaceGraph.GetCellCenterCoordFromIndexOnLevel(((Cube)el).index, pathfindingLevel)).ToList()); //converting List<IVertex> to Lis<Vector3>
}
Close.Add(x);
foreach (var y in graph.Adjacent(x))
{
if (CheckForCancellationRequested())
{
return(null);
}
if (!Close.Contains(y))
{
var newPath = new List <IVertex>(p);
newPath.Add(y);
Open.Add(FFunction(newPath), newPath);
}
}
}
spaceManagerInstance.pathfindingThreadsCurCount--;
return(null);
}
private bool SearchRec(int v, int w)
{
if (v == w)
{
return(true);
}
visited.Add(v);
foreach (int i in graph.Adjacent(v))
{
if (!visited.Contains(i))
{
if (SearchRec(i, w))
{
path.Add(i);
return(true);
}
}
}
return(false);
}
private void BFS(IGraph graph, int start)
{
Queue <int> queue = new Queue <int>();
queue.Enqueue(start);
isConnected[start] = true;
while (queue.Count > 0)
{
int vertex = queue.Dequeue();
foreach (var v in graph.Adjacent(vertex))
{
if (!isConnected[v])
{
edgeTo[v] = vertex;
queue.Enqueue(v);
isConnected[v] = true;
}
}
}
}
public IEnumerator GetWay(RTWayInCubes ReturnWay)
{
Open = new PriorityQueue();
Close = new List <IVertex>();
var s = new List <IVertex>();
s.Add(start);
Open.Add(FFunction(s), s);
int cyclesCount = 0;
while (Open.Count != 0)
{
// choosing the optimum path out of queue
var p = Open.First();
Open.RemoveFirst();
//consideration of its last node
var x = p.Last();
//in case this node has been visited the path is rejected
if (Close.Contains(x))
{
continue;
}
//The path cost is saved and the path is returned if the node is the target point.
if (x.Equals(goal))
{
currentPathLength = 0;
for (int i = 1; i < p.Count; i++)
{
currentPathLength += graph.Cost(p[i], p[i - 1]);
}
firstRun = false;
ReturnWay(p);
break;
}
//Current node is marked as visited
Close.Add(x);
// Disclosure of unvisited adjacent nodes
foreach (var y in graph.Adjacent(x))
{
if (!Close.Contains(y))
{
var newPath = new List <IVertex>(p);
newPath.Add(y);
//During the first launch the algorithm works as a standard A* algorithm
//Otherwise, reject all potential paths if admissible function estimates their cost higher than the cost of the last found path
if (firstRun || FAccessibleFunction(newPath) < currentPathLength)
{
Open.Add(FFunction(newPath), newPath);
}
}
}
if (cyclesCount == 5)
{
cyclesCount = 0;
yield return(null);
}
else
{
cyclesCount++;
}
}
}
public List <City> Adjacent(City city)
{
var cityIdx = _cityIdxLookup[city];
return(_cityGraph.Adjacent(cityIdx).ToList());
}
/// <summary>
/// 计算图中某个顶点的度数
/// </summary>
/// <param name="vertex">要计算度数的顶点</param>
/// <returns>顶点的度数</returns>
public static int Degree(this IGraph graph, int vertex)
{
return(graph.Adjacent(vertex).Count());
}