/**
* Generate a random pyraminx position.
* @param r random int generator
*/
public PyraminxSolverState RandomState(Random r)
{
var state = new PyraminxSolverState();
do
{
state.EdgePerm = r.Next(NEdgePerm);
} while (PrunPerm[state.EdgePerm] == -1); // incorrect permutation (bad parity)
state.EdgeOrient = r.Next(NEdgeOrient);
state.CornerOrient = r.Next(NCornerOrient);
state.Tips = r.Next(NTips);
return(state);
}
private static string Solve(PyraminxSolverState state, int desiredLength, bool exactLength, bool inverse,
bool includingTips)
{
var r = new Random();
var solution = new int[MaxLength];
var foundSolution = false;
// If we count the tips in the desired length, we have to subtract the number of unsolved tips from the length of the main puzzle search.
if (includingTips)
{
desiredLength -= state.UnsolvedTips();
}
var length = exactLength ? desiredLength : 0;
while (length <= desiredLength)
{
if (Search(state.EdgePerm, state.EdgeOrient, state.CornerOrient, 0, length, 42, solution, r))
{
foundSolution = true;
break;
}
length++;
}
if (!foundSolution)
{
return(null);
}
var scramble = new StringBuilder((MaxLength + 4) * 3);
if (inverse)
{
for (var i = length - 1; i >= 0; i--)
{
scramble.Append(" ").Append(InverseMoveToString[solution[i]]);
}
}
else
{
for (var i = 0; i < length; i++)
{
scramble.Append(" ").Append(MoveToString[solution[i]]);
}
}
// Scramble the tips
var arrayTips = new int[4];
UnpackCornerOrient(state.Tips, arrayTips);
for (var tip = 0; tip < 4; tip++)
{
var dir = arrayTips[tip];
if (dir > 0)
{
scramble.Append(" ")
.Append(inverse ? TipToString[tip * 2 + dir - 1] : InverseTipToString[tip * 2 + dir - 1]);
}
}
return(scramble.ToString().Trim());
}
/**
* Return a generator of a given position in exactly length number of turns or not at all.
* Returns either the solution or the generator (inverse solution)
* @param state state
* @param length length of the desired solution
* @param includingTips do we want to include tips in the solution lenght ?
* @return a string representing the solution or the scramble of a random position
*/
public string GenerateExactly(PyraminxSolverState state, int length, bool includingTips)
{
return(Solve(state, length, true, true, includingTips));
}
/**
* Solve a given position in less than or equal to length number of turns.
* Returns either the solution or the generator (inverse solution)
* @param state state
* @param length length of the desired solution
* @param includingTips do we want to include tips in the solution lenght ?
* @return a string representing the solution or the scramble of a random position
*/
public string SolveIn(PyraminxSolverState state, int length, bool includingTips)
{
return(Solve(state, length, false, false, includingTips));
}