private static int HamiltonAllCycles(EulerGraph graph, int[] cycle, int position, ref int numberOfCycles, bool print = false)
{
if (position == cycle.Length)
{
if (graph.IsEdgeExists(cycle[0], cycle[position - 1]))
{
return(1);
}
}
for (int i = 1; i < graph._numberOfVertices; i++)
{
if (IsSafe(i, position, cycle, graph))
{
cycle[position] = i;
if (HamiltonAllCycles(graph, cycle, position + 1, ref numberOfCycles, print) == 1)
{
numberOfCycles++;
if (print)
{
Console.Write(numberOfCycles + ": ");
foreach (var item in cycle)
{
Console.Write(item + " ");
}
Console.WriteLine();
}
}
cycle[position] = -1;
}
}
return(0);
}
private static bool HamiltonCycleUtil(EulerGraph graph, int[] cycle, int position)
{
if (position == cycle.Length)
{
if (graph.IsEdgeExists(cycle[0], cycle[position - 1]))
{
return(true);
}
else
{
return(false);
}
}
for (int i = 1; i < graph._numberOfVertices; i++)
{
if (IsSafe(i, position, cycle, graph))
{
cycle[position] = i;
if (HamiltonCycleUtil(graph, cycle, position + 1))
{
return(true);
}
cycle[position] = -1;
}
}
return(false);
}
public static void CreateReportFromFile()
{
int[][] matrix = File.ReadAllLines("a.txt")
.Select(l => l.Split(' ').Select(i => int.Parse(i)).ToArray())
.ToArray();
var graph = new EulerGraph(matrix.Length);
for (int i = 0; i < matrix.Length; i++)
{
for (int j = 0; j < i; j++)
{
if (matrix[i][j] != 0)
{
graph.AddEdge(i, j);
}
}
}
var cycle = new int[graph._numberOfVertices];
for (int i = 0; i < cycle.Length; i++)
{
cycle[i] = -1;
}
Console.WriteLine($"All Hamilton cycles");
HamiltonCycle.FindAllHamiltonCycles(graph, cycle, true);
Console.WriteLine($"Euler cycle: ");
var eulerCycle = EulerCycle.FindEulerCycle(graph, 0);
foreach (var item in eulerCycle)
{
Console.Write(item + " ");
}
}
public static List <int> FindEulerCycle(EulerGraph graph, int start)
{
var cycle = new Stack <int>();
var stack = new Stack <int>();
var vertex = start;
stack.Push(vertex);
while (stack.Count > 0)
{
var neighbours = graph.GetNeighbours(vertex);
if (neighbours.Count == 0)
{
cycle.Push(stack.Pop());
if (stack.Count == 0)
{
break;
}
vertex = stack.Peek();
continue;
}
var minVertex = neighbours.Min();
graph.RemoveEdge(vertex, minVertex);
stack.Push(minVertex);
vertex = minVertex;
}
return(cycle.ToList());
}
public static void CreateRaport(int start, int step, int numberOfSteps, double saturation, string typeOfRaport)
{
using (StreamWriter output = File.CreateText(RESULTS_DIRECTORY + typeOfRaport + (saturation * 100).ToString() + DateTime.Now.ToString() + ".csv"))
using (CsvWriter csv = new CsvWriter(output, System.Globalization.CultureInfo.CurrentCulture))
{
csv.Configuration.NewLine = NewLine.LF;
csv.Configuration.Delimiter = ",";
if (typeOfRaport == FIRST)
{
csv.WriteHeader(typeof(FirstExcerciseResults));
for (int i = 0; i < numberOfSteps; i++)
{
var stopwatch = new Stopwatch();
stopwatch.Start();
var hamiltonTimes = new int[11];
for (int j = 0; j < 11; j++)
{
var graphHamilton = new EulerGraph(start + (i * step));
graphHamilton.MeetSaturationGoal(saturation);
hamiltonTimes[j] = graphHamilton.MeasureTime(EulerGraph.HAMILTON_CYCLE);
}
Array.Sort(hamiltonTimes);
Console.WriteLine(string.Join(", ", hamiltonTimes));
var graph = new EulerGraph(start + (i * step));
graph.MeetSaturationGoal(saturation);
var result = new FirstExcerciseResults
{
NumberOfVertices = start + (i * step),
HamiltonCycle = hamiltonTimes[5], // Median from 11 results
EulerCycle = graph.MeasureTime(EulerGraph.EULER_CYCLE),
};
csv.NextRecord();
csv.WriteRecord(result);
stopwatch.Stop();
Console.WriteLine(stopwatch.Elapsed);
}
}
else if (typeOfRaport == SECOND)
{
csv.WriteHeader(typeof(SecondExcerciseResults));
for (int i = 0; i < numberOfSteps; i++)
{
var stopwatch = new Stopwatch();
stopwatch.Start();
var graph = new EulerGraph(start + (i * step));
graph.MeetSaturationGoal(saturation);
var result = new SecondExcerciseResults
{
NumberOfVertices = start + (i * step),
Time = graph.MeasureTime(EulerGraph.ALL_HAMILTON_CYCLES),
};
csv.NextRecord();
csv.WriteRecord(result);
stopwatch.Stop();
Console.WriteLine(stopwatch.Elapsed);
}
}
}
}
public static int FindAllHamiltonCycles(EulerGraph graph, int[] cycle, bool print = false)
{
cycle[0] = 0;
int numberOfCycles = 0;
HamiltonAllCycles(graph, cycle, 1, ref numberOfCycles, print);
return(numberOfCycles);
}
/// <summary>
/// Values in a cycle should be different than any vertex in a given graph
/// </summary>
public static bool FindHamiltonCycle(EulerGraph graph, int[] cycle)
{
cycle[0] = 0;
if (!HamiltonCycleUtil(graph, cycle, 1))
{
return(false);
}
return(true);
}
private static bool IsSafe(int v, int position, int[] cycle, EulerGraph graph)
{
if (!graph.IsEdgeExists(v, cycle[position - 1]))
{
return(false);
}
foreach (var vertex in cycle)
{
if (vertex == v)
{
return(false);
}
}
return(true);
}