/// <summary>
/// Reads the input file and files the items list.
/// </summary>
/// <param name="filename">the name of the file to be read</param>
/// <returns>the weight bound for the instance read</returns>
public int ReadInput(string filename)
{
int bound;
List <KnapsackItem> tmpList = new List <KnapsackItem>();
using (StreamReader sr = new StreamReader(filename))
{
bound = Convert.ToInt32(sr.ReadLine());
while (!sr.EndOfStream)
{
string[] pieces = sr.ReadLine().Split(',');
KnapsackItem newItem = new KnapsackItem(Convert.ToInt32(pieces[0]), Convert.ToInt32(pieces[1]), Convert.ToInt32(pieces[2]));
tmpList.Add(newItem);
}
tmpList.Sort();
}
_items = tmpList;
return(bound);
}
/// <summary>
/// Method to find the optimal solution
/// </summary>
/// <param name="filename">input file</param>
public void Solve(string filename)
{
_weightLimit = ReadInput(filename);
CandidateSolution candidate = new CandidateSolution(_items, -1, null);
CandidateSolution best = candidate;
PriorityQueue <int, CandidateSolution> queue = new PriorityQueue <int, CandidateSolution>();
queue.Add(candidate, ComputeBounds(candidate, ref best));
while (queue.Count > 0 && queue.MaximumPriority >= best.Value)
{
CandidateSolution root = queue.RemoveMaximumPriority();
int k = root.Index + 1;
for (int j = k; j < _items.Count; j++)
{
CandidateSolution child = new CandidateSolution(_items, j, root);
if (child.Weight <= _weightLimit)
{
int childBounds = ComputeBounds(child, ref best);
if (childBounds > best.Value)
{
queue.Add(child, childBounds);
}
}
}
}
_totalValue = best.Value;
_totalWeight = best.Weight;
while (best.Previous != null)
{
KnapsackItem tmp = _items[best.Index];
tmp.SelectionText = "X";
_items[best.Index] = tmp;
best = best.Previous;
}
}
