/// <summary>
///
/// </summary>
/// <param name="M"></param>
/// <returns></returns>
public bool SolveStep(SolveMethods M)
{
SolutionStepList L = ComputePossibleSteps(M);
if (L.Count() == 0)
{
return(false);
}
ApplySolutionStep(L.getItem(0));
return(true);
}
/// <summary>
///
/// </summary>
/// <param name="M"></param>
/// <returns></returns>
public SolutionStepList ComputePossibleSteps(SolveMethods M)
{
EnumeratePossibilities();
SolutionStepList L = new SolutionStepList();
// Looking for naked singles
if ((M & SolveMethods.NakedSingles) > 0)
{
for (int i = 0; i < 9; i++)
{
for (int j = 0; j < 9; j++)
{
double index = Math.Log(a[j, i], 2) + 1;
if (index == Math.Floor(index) && a[j, i] > 0 && s[j, i] == 0)
{
L.Add(new SolutionStep(i, j, Convert.ToInt32(index)));
}
}
}
}
// Looking for hidden singles
if ((M & SolveMethods.HiddenSingles) > 0)
{
for (int i = 0; i < 9; i++)
{
for (int j = 0; j < 9; j++)
{
int mask = 0;
for (int m = 0; m < 9; m++)
{
if (m != j)
{
mask |= a[m, i];
}
}
int match = a[j, i] & (511 - mask);
if (s[j, i] == 0 && match > 0)
{
double index = Math.Log(match, 2) + 1;
L.Add(new SolutionStep(i, j, Convert.ToInt32(index)));
}
}
}
}
// Looking for block-hidden singles
if ((M & SolveMethods.BlockHiddenSingles) > 0)
{
for (int i = 0; i < 9; i++)
{
for (int j = 0; j < 9; j++)
{
int blockx = i / 3;
int blocky = j / 3;
int mask = 0;
for (int m = 0; m < 3; m++)
{
for (int n = 0; n < 3; n++)
{
int xindex = blockx * 3 + m;
int yindex = blocky * 3 + n;
if (yindex != j || xindex != i)
{
mask |= a[yindex, xindex];
}
}
}
int match = a[j, i] & (511 - mask);
if (s[j, i] == 0 && match > 0)
{
double index = Math.Log(match, 2) + 1;
L.Add(new SolutionStep(i, j, Convert.ToInt32(index)));
}
}
}
}
return(L);
}