public double Evaluate(IChromosome chromosome)
{
BinaryChromosome knapsackConfiguration = (BinaryChromosome)chromosome;
int length = knapsackConfiguration.Length;
ulong value = knapsackConfiguration.Value;
for (int i = 0; i < length; i++)
{
if ((value & TestBitsMask[i]) == 0)
{
_bag.RemoveItem(_items[i]);
}
else
{
_bag.InsertItem(_items[i]);
}
}
if (_bag.AcceptableWeight())
{
return(_bag.ItemsCost());
}
return(0);
}
public int Solve(KnapsackProblemModel problem)
{
Bag bag = new Bag(problem.BagCapacity);
List <Item> items = problem.Items.ToList();
int count = items.Count;
BitArray possibility = new BitArray(count);
int bestItemsCost = 0;
while (true)
{
for (int i = 0; i < count; i++)
{
//NEXT BIT WILL BE INVERTED
bool next = !possibility[i];
possibility[i] = next;
//IF NEW VALUE IS TRUE INSERT ITEM - IF FALSE REMOVE IT
if (next)
{
bag.InsertItem(items[i]);
}
else
{
bag.RemoveItem(items[i]);
}
//ONE IS SET - END
if (next)
{
break;
}
}
if (bag.IsEmpty())
{
break;
}
if (bag.AcceptableWeight())
{
int itemsCost = bag.ItemsCost();
if (itemsCost > bestItemsCost)
{
bestItemsCost = itemsCost;
}
}
}
return(bestItemsCost);
}
public int Solve(KnapsackProblemModel problem)
{
List <Item> items = problem.Items.ToList();
items.Sort(Item.CostToWeightRatioComparerDescending);
Bag bag = new Bag(problem.BagCapacity);
foreach (Item t in items)
{
bag.InsertItem(t);
if (!bag.AcceptableWeight())
{
bag.RemoveItem(t);
}
}
return(bag.ItemsCost());
}
public int RecursiveSolver(Bag bag, List <Item> items, int bestKnown)
{
if (items.Count > 0)
{
int bestItemsCost = bestKnown;
List <Item> recList = new List <Item>(items);
recList.RemoveAt(0);
int sum = recList.Sum(item => item.Cost) + bag.ItemsCost();
if (sum >= bestKnown)
{
bestItemsCost = RecursiveSolver(bag, recList, bestKnown);
}
bag.InsertItem(items[0]);
if (bag.AcceptableWeight())
{
int itemsCost = bag.ItemsCost();
if (itemsCost > bestItemsCost)
{
bestItemsCost = itemsCost;
}
recList = new List <Item>(items);
recList.Remove(items[0]);
sum = recList.Sum(item => item.Cost) + bag.ItemsCost();
if (sum >= bestItemsCost)
{
bestItemsCost = RecursiveSolver(bag, recList, bestItemsCost);
}
}
bag.RemoveItem(items[0]);
return(bestItemsCost);
}
return(bestKnown);
}