private static void CalculateCombinationSet(BackpackTask backpackTask, CombinationSet set,
TaskProgress service, CancellationToken token)
{
if (token.IsCancellationRequested)
{
return;
}
// iterate over all item combinations
// calculate total weight and price of current item set
var totalWeight = 0;
var totalPrice = 0;
foreach (var itemCombination in set.ItemCombinations)
{
totalWeight += itemCombination.Item.Weight;
totalPrice += itemCombination.Item.Price;
}
// check if we ok with totalWeight and current price of item set is greater that current best item set price
if (totalWeight <= backpackTask.WeightLimit &&
totalPrice > backpackTask.BestItemSetPrice)
{
// update current solution
backpackTask.BestItemSetPrice = totalPrice;
backpackTask.BestItemSetWeight = totalWeight;
List <Item> items = new List <Item>();
foreach (var itemCombo in set.ItemCombinations)
{
items.Add(itemCombo.Item);
}
backpackTask.BestItemSet = new List <BestItemSet>();
foreach (var item in items)
{
backpackTask.BestItemSet.Add(new BestItemSet()
{
Item = item
});
}
}
service.UpdateProgress();
}
public async Task StartBackpackTask(string id, CancellationToken token)
{
var unitOfWork = UnitOfWork.UnitOfWorkFactory();
BackpackTask backpackTask = unitOfWork.BackpackTaskRepository.Get(id);
TaskProgress taskProgress = new TaskProgress(backpackTask);
CalculationService.StartCalculation(backpackTask, taskProgress, token);
if (token.IsCancellationRequested)
{
await unitOfWork.CompleteAsync();
return;
}
backpackTask.EndTime = DateTime.Now;
backpackTask.Complete = true;
unitOfWork.CombinationSetRepository.RemoveRange(backpackTask.CombinationSets);
await unitOfWork.CompleteAsync();
}
public static void StartCalculation(BackpackTask backpackTask, TaskProgress service, CancellationToken token)
{
List <Item> set = backpackTask.BackpackItems;
List <CombinationSet> result = backpackTask.CombinationSets;
if (set.Count > 0 && !result.Where(l => l.ItemCombinations.Count == set.Count).Any(l =>
{
List <Item> items = l.ItemCombinations.Select(argItemCombination => argItemCombination.Item).ToList();
return(items.SequenceEqual(set));
}))
{
CombinationSet combinationSet = new CombinationSet {
ItemCombinations = set.Select(item => new ItemCombination {
Item = item
}).ToList()
};
result.Add(combinationSet);
CalculateCombinationSet(backpackTask, combinationSet, service, token);
}
GenerateCombinationRecursive(backpackTask, set, result, service, token);
}
private static void GenerateCombinationRecursive(BackpackTask backpackTask, List <Item> set, List <CombinationSet> result, TaskProgress service, CancellationToken token)
{
for (int i = 0; i < set.Count; i++)
{
if (token.IsCancellationRequested)
{
return;
}
List <Item> temp = new List <Item>(set.Where((s, index) => index != i));
if (temp.Count > 0 && !result.Where(l => l.ItemCombinations.Count == temp.Count).Any(l =>
{
List <Item> items = l.ItemCombinations.Select(argItemCombination => argItemCombination.Item).ToList();
return(items.SequenceEqual(temp));
}))
{
CombinationSet combinationSet = new CombinationSet {
ItemCombinations = temp.Select(item => new ItemCombination {
Item = item
}).ToList()
};
result.Add(combinationSet);
CalculateCombinationSet(backpackTask, combinationSet, service, token);
GenerateCombinationRecursive(backpackTask, temp, result, service, token);
}
}
}
