public KnightSolutionEnumerator(ArrayListHashtable hatesMap, ArrayListHashtable needsMap, int knightsNumber)
{
this.hatesMap = hatesMap;
this.needsMap = needsMap;
this.KnightsNumber = knightsNumber;
this.PartialSolution = new KnightSolution(KnightsNumber);
}
private bool IsConsistent(KnightSolution solution, int prevIndex, int index, int nextIndex)
{
// if (solution.ToString().IndexOf("acmnbhgediljfk") != -1)
// //if (solution.ToString().IndexOf("anmckfjlideghb") != -1)
// {
// Console.WriteLine();
// }
// get neighbors
char knight = solution.Knights[index];
char prevNeighbor = ' ';
char nextNeighbor = ' ';
if (prevIndex >= 0)
{
prevNeighbor = solution.Knights[prevIndex];
}
if (nextIndex >= 0)
{
nextNeighbor = solution.Knights[nextIndex];
}
IList prevNeighborHatesList = hatesMap[prevNeighbor];
IList prevNeighborNeedsList = needsMap[prevNeighbor];
IList nextNeighborHatesList = hatesMap[nextNeighbor];
IList nextNeighborNeedsList = needsMap[nextNeighbor];
IList knightHatesList = hatesMap[knight];
IList knightNeedsList = needsMap[knight];
if ((knightHatesList != null && knightHatesList.Contains(prevNeighbor)) ||
(knightHatesList != null && knightHatesList.Contains(nextNeighbor)) ||
(prevNeighborHatesList != null && prevNeighborHatesList.Contains(knight)) ||
(nextNeighborHatesList != null && nextNeighborHatesList.Contains(knight)))
{
return(false);
}
if ((prevNeighbor != ' ') && nextNeighbor != ' ')
{
if (knightNeedsList != null &&
(!knightNeedsList.Contains(prevNeighbor) && !knightNeedsList.Contains(nextNeighbor)))
{
//Console.WriteLine(prevNeighbor + ":" + knight + ":" + nextNeighbor);
//Console.Write(solution);
return(false);
}
}
return(true);
}
public ISolution Clone()
{
KnightSolution clone = new KnightSolution(KnightsNumber);
clone.Knights = new char[KnightsNumber];
for (int i = 0; i < KnightsNumber; i++)
{
clone.Knights[i] = Knights[i];
}
clone.NextKnightIndex = NextKnightIndex;
return(clone);
}
public bool FillDescendantSolution(ISolution nextSolution)
{
KnightSolution solution = (KnightSolution)nextSolution;
solution.NextKnightIndex = PartialSolution.NextKnightIndex + 1;
solution.Knights = new char[KnightsNumber];
for (int i = 0; i < KnightsNumber; i++)
{
solution.Knights[i] = PartialSolution.Knights[i];
}
for (; NextKnight < KnightsNumber; NextKnight++)
{
bool knightAlreadyPositioned = false;
char newKnight = (char)('a' + NextKnight);
for (int j = 0; j < PartialSolution.NextKnightIndex; j++)
{
// check if the knight already placed
if (PartialSolution.Knights[j] == newKnight)
{
knightAlreadyPositioned = true;
}
}
if (!knightAlreadyPositioned)
{
int index = PartialSolution.NextKnightIndex;
solution.Knights[PartialSolution.NextKnightIndex] = newKnight;
// check for previous
if (index > 1 && !IsConsistent(solution, index - 2, index - 1, index))
{
continue;
}
if (index == KnightsNumber - 1)
{
if (!IsConsistent(solution, index - 1, index, 0))
{
continue;
}
if (!IsConsistent(solution, index, 0, 1))
{
continue;
}
}
else if (!IsConsistent(solution, index - 1, index, index + 1))
{
continue;
}
NextKnight++;
return(true);
}
}
return(false);
}
