//Dynamic programming algorithm
private static Knapsack FillKnapsack(int maxWeight, List <Item> items)
{
Knapsack[] sacks = new Knapsack[maxWeight + 1];
sacks[0] = new Knapsack(0);
Knapsack bestSack;
for (int w = 1; w <= maxWeight; w++)
{
bestSack = sacks[w - 1];
sacks[w] = new Knapsack(w);
for (int i = 0; i < items.Count; i++)
{
int currVal = items[i].value;
int currWeight = items[i].weight;
if (currWeight < w)
{
if ((sacks[w - currWeight].value + currVal) > bestSack.value)
{
bestSack = new Knapsack(w);
foreach (Item item in sacks[w - currWeight])
{
bestSack.Add(item);
}
bestSack.Add(items[i]);
}
}
else if (currWeight == w)
{
if (currVal > bestSack.value)
{
bestSack = new Knapsack(w);
bestSack.Add(items[i]);
}
}
}
sacks[w] = bestSack;
}
return(sacks[maxWeight]);
}
public static void KnapsackProblem()
{
Console.WriteLine("Task#6 (items are infinite)");
List <Item> items = new List <Item>();
if (GetInput(items))
{
//Getting max weight capacity
Console.WriteLine("Input an integer knapsack max weight capacity:");
var consoleInput = Console.ReadLine();
//Trying to parse the input
int capacity = 0;
if (!int.TryParse(consoleInput, out capacity) || capacity <= 0)
{
Console.WriteLine($"\"{consoleInput}\" is too big, too small or is not an integer");
return;
}
Knapsack sack = FillKnapsack(capacity, items);
//Writing contained items, sum of values and weights to console
Console.WriteLine("Knapsack contains:");
int sackWeight = 0;
foreach (Item item in sack)
{
Console.Write($"(v:{item.value}, w:{item.weight}) ");
sackWeight += item.weight;
}
Console.WriteLine($"\nSum: (v:{sack.value}, w:{sackWeight}/{capacity})\n" +
$"Knapsack value is: {sack.value}");
Console.WriteLine();
}
else
{
return;
}
}