public int FindMinCutKargerStein()
{
_edgesList = GraphGenerator.CreateEdgesList(_graphArray);
var graph = new UnionFind(_verticesCount);
return(FindMinCutKargerSteinRecursive(graph, _verticesCount));
}
private int FindMinCutAdjacencyListOnce(Random generator)
{
_adjacencyList = GraphGenerator.CreateAdjacencyList(_graphArray);
while (_adjacencyList.Count > 2)
{
var randomNum = generator.Next(_adjacencyList.Count);
var start = _adjacencyList.Keys.ElementAt(randomNum);
var startEdges = _adjacencyList[start];
var finish = startEdges[generator.Next(startEdges.Count)];
var finishEdges = _adjacencyList[finish];
startEdges.RemoveAll(x => x == finish);
foreach (var vertex in finishEdges)
{
if (vertex == start)
{
continue;
}
startEdges.Add(vertex);
_adjacencyList[vertex].RemoveAll(x => x == finish);
_adjacencyList[vertex].Add(start);
}
_adjacencyList.Remove(finish);
}
return(_adjacencyList[_adjacencyList.Keys.ElementAt(0)].Count);
}
//TODO: Init adjacency list with actual node ids instead of consecutive numbers
private Dictionary <int, List <int> > ReverseEdges(Dictionary <int, List <int> > graph)
{
var reversedGraph = new Dictionary <int, List <int> >(_nodeCount);
GraphGenerator.InitializeAdjacencyList(reversedGraph, _nodeCount);
foreach (var node in graph)
{
var tailNode = node.Key;
foreach (var headNode in graph[tailNode])
{
reversedGraph[headNode].Add(tailNode);
}
}
return(reversedGraph);
}
public int FindMinCutUnion()
{
_edgesList = GraphGenerator.CreateEdgesList(_graphArray);
var trialsNumber = GetDefaultTrials();
var lowestCut = int.MaxValue;
for (int i = 0; i < trialsNumber; i++)
{
var randomGenerator = new Random(i);
var currentCut = FindMinCutUnionOnce(randomGenerator);
if (currentCut > lowestCut)
{
continue;
}
lowestCut = currentCut;
}
return(lowestCut);
}
