public bool extend()
{
if (citiesLeft.Count() != 0)
{
foreach (int i in citiesLeft)
{
double initialCost = matrix[path.Last()][i] + cost;
double[][] newMatrix = this.matrix.Select(a => a.ToArray()).ToArray();
for (int j = 0; j < matrix.Count(); j++)
{
newMatrix[path.Last()][j] = Double.PositiveInfinity;
newMatrix[j][i] = Double.PositiveInfinity;
}
List <int> newPath = path.Select(a => a).ToList();
newPath.Add(i);
List <int> newCitiesLeft = citiesLeft.Select(a => a).ToList();
newCitiesLeft.Remove(i);
BBState state = new BBState(newMatrix, newPath, newCitiesLeft, initialCost);
PriorityQueue.getInstance().insert(state);
}
return(false);
}
else
{
cost = matrix[path.Last()][0] + cost;
path.Add(0);
return(true);
}
}
/// <summary>
/// performs a Branch and Bound search of the state space of partial tours
/// stops when time limit expires and uses BSSF as solution
/// </summary>
/// <returns>results array for GUI that contains three ints: cost of solution, time spent to find solution, number of solutions found during search (not counting initial BSSF estimate)</returns>
public string[] bBSolveProblem()
{
string[] results = new string[3];
double bssf = Double.PositiveInfinity;
// TODO: Add your implementation for a branch and bound solver here.
//List<int> citiesLeft = new List<int>();
//double[][] matrix = new double[Cities.Length][];
//for (int i = 0; i < Cities.Length; i++)
//{
// citiesLeft.Add(i);
// matrix[i] = new double[Cities.Length];
// for (int j = 0; j < Cities.Length; j++)
// {
// if (i != j)
// matrix[i][j] = Cities[i].costToGetTo(Cities[j]);
// else
// matrix[i][j] = Double.PositiveInfinity;
// }
//}
//citiesLeft.RemoveAt(0);
double[][] matrix = new double[4][];
matrix[0] = new double[4] {
Double.PositiveInfinity, 7, 3, 12
};
matrix[1] = new double[4] {
3, Double.PositiveInfinity, 6, 14
};
matrix[2] = new double[4] {
5, 8, Double.PositiveInfinity, 6
};
matrix[3] = new double[4] {
9, 3, 5, Double.PositiveInfinity
};
BBState state = new BBState(matrix, new List <int>()
{
0
}, new List <int>()
{
1, 2, 3
}, 0);
//BBState state = new BBState(matrix, new List<int>() { 0 }, citiesLeft,0);
PriorityQueue.getInstance().insert(state);
BBState current;
while (!PriorityQueue.getInstance().isEmpty())
{
current = PriorityQueue.getInstance().deletemin();
if (state.extend())
{
if (current.getCost() < bssf)
{
bssf = current.getCost();
PriorityQueue.getInstance().trim(bssf);
}
}
}
results[COST] = "not implemented"; // load results into array here, replacing these dummy values
results[TIME] = "-1";
results[COUNT] = "-1";
return(results);
}