private static double MinPrice(ImmutableHashSet <Node> nodesIn, Graph graph,
ImmutableHashSet <Node> prohibitedNodes, int setSize)
{
ImmutableDictionary <Node, double> priceOfNode = ImmutableDictionary <Node, double> .Empty;
var usedNodes = nodesIn.Union(prohibitedNodes);
foreach (var node in nodesIn)
{
var price = 0.0;
foreach (var adjacentNode in nodesIn)
{
if (!node.Equals(adjacentNode))
{
price += graph.Weights[node][adjacentNode];
}
}
price += graph.Weights[node].RemoveKeys(usedNodes).Values.PartialSort(setSize - nodesIn.Count).Sum();
priceOfNode = priceOfNode.Add(node, price);
}
foreach (var graphNode in graph.Nodes)
{
if (!usedNodes.Contains(graphNode))
{
var price = 0.0;
foreach (var adjacentNode in nodesIn)
{
price += graph.Weights[graphNode][adjacentNode];
}
if (setSize > nodesIn.Count)
{
price += graph.Weights[graphNode].RemoveKeys(usedNodes).Values.PartialSort(setSize - nodesIn.Count - 1).Sum();
}
priceOfNode = priceOfNode.Add(graphNode, price);
}
}
double inPrice = nodesIn.Sum(n => priceOfNode[n]) / 2.0;
double restPrice = priceOfNode.RemoveRange(nodesIn).Values.PartialSort(setSize - nodesIn.Count).Sum() / 2.0;
return(inPrice + restPrice);
}
public int Sum() => Elements.Sum(e => e.Value);
