/// <summary>
/// Adds the given item to the container. An exception is thrown if
/// an item with the same description is already in the container.
/// </summary>
public virtual void AddItem(BackPackItem item)
{
if (_items.ContainsKey(item.Description))
{
throw new ArgumentException(item.Description + " is already in the " + _containerDescription + "!");
}
_items.Add(item.Description, item);
}
/// <summary>
/// Extends the base version with a check for weight capacity
/// </summary>
public override void AddItem(BackPackItem item)
{
if (item.Weight > WeightCapacityLeft)
{
throw new ArgumentException("Oops, you over-stuffed the BackPack!!");
}
base.AddItem(item);
}
public override void Solve(double capacityLeft)
{
string description = PickNextItemFromVault(capacityLeft);
if (description != string.Empty)
{
BackPackItem item = TheVault.RemoveItem(description);
TheBackPack.AddItem(item);
Solve(TheBackPack.WeightCapacityLeft);
}
}
/// <summary>
/// Removes and returns the item corresponding to the given description.
/// An exception is thrown if no matching item is found.
/// </summary>
public virtual BackPackItem RemoveItem(string description)
{
if (!_items.ContainsKey(description))
{
throw new ArgumentException(description + " is not in the " + _containerDescription + "!");
}
BackPackItem removedItem = _items[description];
_items.Remove(description);
return(removedItem);
}
private string PickNextItemFromVault(double capacityLeft)
{
double bestRatio = 0;
BackPackItem bestItem = null;
foreach (var item in TheVault.Items)
{
if (item.Weight <= capacityLeft)
{
double ratio = item.Value / item.Weight;
if (ratio > bestRatio)
{
bestRatio = ratio;
bestItem = item;
}
}
}
return((bestItem != null) ? bestItem.Description : string.Empty);
}
