/// <summary>
/// Test closest more than value threshold problem.
/// </summary>
public void TestCase2()
{
const double KNAPSACK_CAPACITY = 300;
const int ITEM_NUM = 16;
double[] weight = new double[ITEM_NUM] {
355, 367, 192, 100, 228, 456, 2714, 157, 151.9, 53, 98, 210, 111, 266, 276, 94
};
double[] price = new double[ITEM_NUM] {
1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0
};
int i = 0;
foreach (double w in weight)
{
if ((i++ % 4) == 0)
{
Console.Write("\n");
}
Console.Write(" {0,7},", w.ToString("F2"));
}
List <Item> l = KnapsackSol.GenerateItems(weight, price);
do
{
Console.WriteLine("\nPlease input a number as capacity ('Q' to quit):");
string str = Console.ReadLine();
double capacity;
if (false == double.TryParse(str, out capacity))
{
if (str.CompareTo("Q") == 0)
{
Console.WriteLine("You quit the program!");
break;
}
else
{
Console.WriteLine("Can't recognize the input number: {0}", str);
continue;
}
}
else
{
WeightNode wn = KnapsackSol.FindItemCollectionWithMostMatchValue(l, capacity);
if (wn != null)
{
Console.WriteLine(wn.ToString());
}
else
{
Console.WriteLine("No solution!");
}
}
} while (true);
}
/// <summary>
/// Test 0-1 knapsack problem with random values and weights.
/// </summary>
public void TestCase0()
{
const int TOTAL_ITEMS_NUM = 20;
const double WEIGHT_MEAN = 4.0;
const double VALUE_MEAN = 10.0;
const double CAPACITY = 40.0;
var v = KnapsackSol.GenerateGroceries(TOTAL_ITEMS_NUM, WEIGHT_MEAN, VALUE_MEAN, 1);
WeightNode wn = KnapsackSol.Process(v, CAPACITY);
Console.WriteLine(wn.ToString());
}
/// <summary>
/// Test 0-1 knapsack problem with fixed values and weights.
/// </summary>
public void TestCase1()
{
const int ITEM_NUM = 10;
const double KNAPSACK_CAPACITY = 30;
double[] weight = new double[ITEM_NUM] {
1, 9, 3, 6, 5, 4, 7, 2, 8, 10
};
double[] price = new double[ITEM_NUM] {
2, 8, 9, 4, 7, 3, 1, 6, 5, 10
};
List <Item> l = KnapsackSol.GenerateItems(weight, price);
WeightNode wn = KnapsackSol.Process(l, KNAPSACK_CAPACITY);
Console.Write(wn.ToString());
}
public WeightNode(WeightNode node)
{
_Value = node._Value;
_Weight = node._Weight;
ItemsList.AddRange(node.ItemsList);
}
/// <summary>
/// Find the closest collection more than ValueThreshold.
/// </summary>
/// <param name="Items"></param>
/// <param name="WeightThreshold"></param>
/// <returns></returns>
public static WeightNode FindItemCollectionWithMostMatchValue(IEnumerable <Item> Items, double WeightThreshold)
{
int i;
int numOfMoreThanThreshold = 0;
const int BEST_SOLUTION_NUM = 3;
double maxWeight = 0.0;
WeightNode dummy = new WeightNode()
{
_Value = 0.0, _Weight = 0.0
};
LinkedList <WeightNode> retList = new LinkedList <WeightNode>();
LinkedListNode <WeightNode> node = null;
LinkedListNode <WeightNode> moreWeighNode = null;
retList.AddLast(dummy);
foreach (Item g in Items)
{
for (i = 0; i < g.Number; i++)
{
node = retList.Last;
moreWeighNode = retList.Last;
maxWeight = retList.Last.Value._Weight;
while (node != null)
{
double totalWeight = node.Value._Weight + g.Weight;
while (moreWeighNode != null)
{
if (Math.Abs(totalWeight - moreWeighNode.Value._Weight) < 0.001)
{
if (node.Value._Value + g.Value > moreWeighNode.Value._Value)
{
// employ the current node + the current grocery
WeightNode wn = new WeightNode(node.Value);
wn.AddItem(g);
moreWeighNode.Value = wn;
}
break;
}
else if (totalWeight < moreWeighNode.Value._Weight)
{
moreWeighNode = moreWeighNode.Previous;
}
else if (totalWeight > moreWeighNode.Value._Weight)
{
if ((totalWeight < maxWeight) || (totalWeight < WeightThreshold) ||
((totalWeight > WeightThreshold) && (numOfMoreThanThreshold < BEST_SOLUTION_NUM)))
{
WeightNode wn = new WeightNode(node.Value);
wn.AddItem(g);
retList.AddAfter(moreWeighNode, new LinkedListNode <WeightNode>(wn));
moreWeighNode = moreWeighNode.Next;
if (totalWeight > WeightThreshold)
{
if (numOfMoreThanThreshold > BEST_SOLUTION_NUM)
{
retList.RemoveLast();
}
else
{
numOfMoreThanThreshold++;
}
}
maxWeight = retList.Last.Value._Weight;
}
break;
}
}
node = node.Previous;
}
}
}
return(retList.First(o => (o._Weight >= WeightThreshold)));
}
/// <summary>
/// Select some grocery from Groceries and make sure
/// 1. the total weight is less than MaxWeight
/// 2. the total value is highest.
///
/// </summary>
/// <param name="Groceries"></param>
/// <param name="MaxWeight"></param>
/// <returns></returns>
public static WeightNode Process(IEnumerable <Item> Groceries, double MaxWeight)
{
/*
* (Value/Weight)
*
* retList
* |
* +- dummy (0.0/0.0)
* |
* +- WeightNode (V/W) --> Item0 -> Item1 -> ... -> ItemN
* |
* + ...
* |
* +- WeightNode (V/Capacity) -> Item0 -> Item1 -> ... ItemN
*
*/
int i;
WeightNode dummy = new WeightNode()
{
_Value = 0.0, _Weight = 0.0
};
LinkedList <WeightNode> retList = new LinkedList <WeightNode>();
LinkedListNode <WeightNode> node = null;
LinkedListNode <WeightNode> moreWeighNode = null;
retList.AddLast(dummy);
foreach (Item g in Groceries)
{
for (i = 0; i < g.Number; i++)
{
node = retList.Last;
moreWeighNode = retList.Last;
while (node != null)
{
double totalWeight = node.Value._Weight + g.Weight;
if (totalWeight <= MaxWeight)
{
while (moreWeighNode != null)
{
if (Math.Abs(totalWeight - moreWeighNode.Value._Weight) < 0.001)
{
if (node.Value._Value + g.Value > moreWeighNode.Value._Value)
{
// employ the current node + the current grocery
WeightNode wn = new WeightNode(node.Value);
wn.AddItem(g);
moreWeighNode.Value = wn;
}
break;
}
else if (totalWeight < moreWeighNode.Value._Weight)
{
moreWeighNode = moreWeighNode.Previous;
}
else if (totalWeight > moreWeighNode.Value._Weight)
{
WeightNode wn = new WeightNode(node.Value);
wn.AddItem(g);
//moreWeighNode.AddGrocery(g);
retList.AddAfter(moreWeighNode, new LinkedListNode <WeightNode>(wn));
moreWeighNode = moreWeighNode.Next;
break;
}
}
}
node = node.Previous;
}
}
}
double maxValue = retList.Max(o => o._Value);
return(retList.Last(o => (o._Value == maxValue)));
}