public HeldKarpAlgorithm(Graph graph, int startVertex)
{
_graph = graph;
_result = new AlgorithmResult();
_startVertex = startVertex;
_weightOfSets = new Dictionary <string, int>();
}
public BruteForceAlgorithm(Graph graph)
{
_graph = graph;
_result = new AlgorithmResult
{
Weight = Int32.MaxValue
};
}
public void Invoke()
{
_weightOfSets.Clear();
var tempGraph = _graph.Vertices.ToHashSet();
tempGraph.Remove(_startVertex);
_result = HeldKarp(_startVertex, tempGraph);
_result.Path.Reverse();
}
public void Invoke()
{
var init = TabuAlgorithmResult.GenerateResult(_graph.NumberOfCities);
init.CalculateWeight(_graph);
var result = TabuSearch(init);
Result = new AlgorithmResult {
Path = result.Path, Weight = result.Weight
};
}
private AlgorithmResult HeldKarp(int end, HashSet <int> verticesSet)
{
if (!verticesSet.Any())
{
//jezeli zbior jest pusty to zwracamy wynik dla wierzchołka końcowego dla danego wywołania i startowego globalnego
var result = new AlgorithmResult()
{
Weight = _graph.GetWeight(end, _startVertex)
};
result.Path.Add(_startVertex);
result.Path.Add(end);
return(result);
}
int totalWeight = Int32.MaxValue;
var reccurResult = new AlgorithmResult();
foreach (var vertex in verticesSet)
{
//zbior bez obecnego wierzchołka
var tempSet = new HashSet <int>(verticesSet);
tempSet.Remove(vertex);
var otherResult = new AlgorithmResult();
string Path;
//sciezka
Path = $"{_startVertex},";
if (tempSet.Any())
{
Path += string.Join(",", tempSet) + ",";
}
Path += $"{vertex},";
//jezeli waga dla sciezki bez obecnego wierzchołka znajduje sie w słowniku to ja pobieramy
if (!_weightOfSets.TryGetValue(Path, out var weightFromMemory))
{
//jezeli nie to wywołujemy rekurencję
otherResult = HeldKarp(vertex, tempSet);
//i zapisujemy do słownika
var innerPath = string.Join(",", otherResult.Path) + ",";
_weightOfSets[innerPath] = otherResult.Weight;
}
else
{
//jezeli jest w słowniku to przepisujemy wagę
otherResult.Weight = weightFromMemory;
otherResult.Path = new List <int>();
otherResult.Path.Add(_startVertex);
otherResult.Path.AddRange(tempSet);
otherResult.Path.Add(vertex);
}
int weight = _graph.GetWeight(end, vertex);
//waga całego cyklu
int currentWeight = weight + otherResult.Weight;
//jezeli jest to najkrótsza z dotychczasowych sciezek to ja zapisuje do rozwiazania koncowego
if (currentWeight < totalWeight)
{
totalWeight = currentWeight;
reccurResult.Weight = currentWeight;
reccurResult.Path = otherResult.Path;
reccurResult.Path.Add(end);
}
}
return(reccurResult);
}
