public enum Operator { MUL = 42, ADD = 43, SUB = 45, DIV = 47 } // Ascii codes
/// <summary>Creator used by Interface to create initial base of numbers</summary>
/// <param name="initialBaseNumber">Users input parameters</param>
public Base(ulong[] initialBaseNumber)
{
int length = initialBaseNumber.Length;
Array.Sort(initialBaseNumber);
BaseNb = new Nbr[length];
for (int k = 0; k < length; k++)
{
BaseNb[k] = new Nbr(initialBaseNumber[k]);
}
}
/// <summary>Will eventually memorise best solutions</summary>
/// <param name="number">A candidate</param>
/// <returns>Modify sol HashSet of best solutions</returns>
public bool CheckCandidate(Nbr number)
{
ulong proximity = (target > number.Val) ? (target - number.Val) : (number.Val - target); // Math.Abs(ulong) doesn't exist
if (proximity <= best)
{
if (proximity < best)
{
best = proximity; // Better solution found iff strict inegality
for (int k = 0; k < MAX; k++)
{
sol[k].Clear(); // Erase all previous solutions
}
}
sol[number.Level].Add(number.Val + "=" + number.Path);
return(true);
}
else
{
return(false);
}
}
/// <summary>Build all possible set of numbers combining existing pairs of numbers</summary>
/// <returns>A new base if possible, nothing else</returns>
/// <remarks>Iterator used in Search.loop foreach</remarks>
/// <note>
/// Idea#1: directly build a sorted base using the fact that numbers are already sorted
/// Idea#2: reuse numbers and bases to avoid garbage collector
/// Gain..: between 20 to 60% faster (we actually try those tricks)
/// Lost..: awfull lisibility and a lot of more lines of code
/// </note>
public IEnumerable <Base> BuildNextBase()
{
Nbr twin = new Nbr(0); // To eliminate duplicated bases build with same numbers
for (int inA = 0; inA < BaseNb.Length - 1; inA++)
{
Nbr nbrA = BaseNb[inA]; // foreach (Nbr nbrA in BaseNb)
if (nbrA.Path != twin.Path) // Values and ancestors are the same, so they are twins
{
twin = nbrA; // Two twins will follow because the numbers are sorted
for (int inB = inA + 1; inB < BaseNb.Length; inB++)
{
Nbr nbrB = BaseNb[inB]; // foreach (Nbr nbrB in BaseNb)
foreach (Operator op in Enum.GetValues(typeof(Operator)))
{
Nbr newNbr = new Nbr(nbrA, nbrB, op); // Combine all pairs with all operators
if (newNbr.Val != 0) // This is a valid operation
{
List <Nbr> newBase = new List <Nbr> {
newNbr
}; // Build new base with newNbr
foreach (Nbr nbr in BaseNb) // Copy all existing numbers
{
if (nbr != nbrA && nbr != nbrB) // Jump over newNbr parents
{
newBase.Add(nbr);
}
}
newBase.Sort(); // Sort necessary for twins prune mecanism
yield return(new Base(newBase.ToArray(), newNbr));
}
}
}
}
}
}
/// <summary>Creator used by buildNextBase</summary>
/// <param name="numbers">The full array of numbers</param>
/// <param name="lastNumber">Last build number will be checked as solution candidate</param>
public Base(Nbr[] numbers, Nbr lastNumber)
{
LastNb = lastNumber;
BaseNb = numbers;
}