protected bool CheckAddSolution(CountdownNumber number)
{
bool match = number.Value == puzzle.solution;
if (match)
{
solutions.Add(number);
}
return(match);
}
/// <summary>
/// Tries every group against every other group
/// </summary>
private void CombineAll()
{
var hashes = container.GetHashes(); //do I need to copy?
var count = hashes.Count;
for (int first = 0; first < count; first++)
{
for (int second = first + 1; second < count; second++)
{
if (CountdownNumber.CanCombine(hashes[first], hashes[second]))
{
CombineTwoSets(hashes[first], hashes[second]);
}
}
}
}
private void CombineTwoSets(int firstHash, int secondHash)
{
Debug.Assert(CountdownNumber.CanCombine(firstHash, secondHash));
var firstList = container.GetNumbers(firstHash);
var secondList = container.GetNumbers(secondHash);
//pre-allocate results list
var results = new List <CountdownNumber>(3 * firstList.Count * secondList.Count); //3 is the magic number (of operations)
foreach (var n1 in firstList)
{
foreach (var n2 in secondList)
{
foreach (var op in Enum.GetValues(typeof(ComboCountdownNumber.Operation)).Cast <ComboCountdownNumber.Operation>())
{
results.Add(new ComboCountdownNumber(n1, n2, op));
}
}
}
}
public ComboCountdownNumber(CountdownNumber parentA, CountdownNumber parentB, Operation operation)
{
if (operation == Operation.SUBTRACT && parentA.Value < parentB.Value)
{
//special case to keep all numbers positive
this.parentA = parentB;
this.parentB = parentA;
}
else
{
//default don't change ordering.
this.parentA = parentA;
this.parentB = parentB;
}
//calculate the value and hash.
this.operation = operation;
this.Value = CalculateValue();
this.NumbersHash = parentA.CombineHash(ref parentB);
Debug.Assert(this.Value >= 0);
}
/// <summary>
///
/// </summary>
/// <param name="other"></param>
/// <returns>the combined hash of the two numbers</returns>
public int CombineHash(ref CountdownNumber other)
{
return(CombineHash(this.NumbersHash, other.NumbersHash));
}
/// <summary>
/// Tests if the numbers can be combined i.e. the result won't use any duplicate numbers.
/// </summary>
/// <param name="other"></param>
/// <returns></returns>
public bool CanCombine(ref CountdownNumber other)
{
return(CanCombine(this.NumbersHash, other.NumbersHash));
}
