private static void CombineUndirectedCyclicGraphs <TKey>(this Node <TKey, UndirectedCyclicGraph <TKey> > node)
where TKey : struct
{
UndirectedCyclicGraph <TKey> firstGraph = node.GraphsThatIncludeThisNode
.Cast <UndirectedCyclicGraph <TKey> >().First();
foreach (var graphToCombineFrom in node.GraphsThatIncludeThisNode
.Cast <UndirectedCyclicGraph <TKey> >()
.Where(n => !n.Equals(firstGraph))
.ToList())
{
foreach (var graphsNode in graphToCombineFrom.Nodes.Values)
{
firstGraph.AddNode(graphsNode);
}
graphToCombineFrom.ClearNodes();
}
}
public long SolveCase(int numOfCities, int numOfRoads, long libCost, long roadCost, IEnumerable <Tuple <int, int> > roads)
{
var easyCasesResult = CheckEasyCases(numOfCities, numOfRoads, libCost, roadCost, roads);
if (easyCasesResult.HasValue)
{
return(easyCasesResult.Value);
}
HashSet <UndirectedCyclicGraph <int> > graphs = new HashSet <UndirectedCyclicGraph <int> >();
Node <int, UndirectedCyclicGraph <int> >[] nodes = Enumerable.Range(1, numOfCities).Select(idx => new Node <int, UndirectedCyclicGraph <int> >(idx)).ToArray();
foreach (var road in roads)
{
var firstNode = nodes[road.Item1 - 1];
var secondNode = nodes[road.Item2 - 1];
if (graphs.Count == 0)
{
graphs.Add(UndirectedCyclicGraph <int> .CreateNewFromFirstEdge(firstNode, secondNode));
}
else
{
UndirectedCyclicGraph <int> graph = firstNode.GraphsThatIncludeThisNode.FirstOrDefault() as UndirectedCyclicGraph <int> ??
secondNode.GraphsThatIncludeThisNode.FirstOrDefault() as UndirectedCyclicGraph <int>;
if (graph == null)
{
graphs.Add(UndirectedCyclicGraph <int> .CreateNewFromFirstEdge(firstNode, secondNode));
}
else
{
graph.AddEdgeWithNodes(firstNode, secondNode);
}
}
}
var nodesWithNoRoads = CombineAllGraphsOf(nodes);
return(new HashSet <UndirectedCyclicGraph <int> >(nodes.SelectMany(n => n.GraphsThatIncludeThisNode))
.Sum(graph => roadCost * (graph.Nodes.Count - 1) + libCost) + nodesWithNoRoads * libCost);
}
