// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// Check if the cube string s represents a solvable cube.
// 0: Cube is solvable
// -1: There is not exactly one facelet of each colour
// -2: Not all 12 edges exist exactly once
// -3: Flip error: One edge has to be flipped
// -4: Not all corners exist exactly once
// -5: Twist error: One corner has to be twisted
// -6: Parity error: Two corners or two edges have to be exchanged
//
/**
* Check if the cube definition string s represents a solvable cube.
*
* @param s is the cube definition string , see {@link Facelet}
* @return 0: Cube is solvable<br>
* -1: There is not exactly one facelet of each colour<br>
* -2: Not all 12 edges exist exactly once<br>
* -3: Flip error: One edge has to be flipped<br>
* -4: Not all 8 corners exist exactly once<br>
* -5: Twist error: One corner has to be twisted<br>
* -6: Parity error: Two corners or two edges have to be exchanged
*/
public static int verify(String s)
{
int[] count = new int[6];
try
{
for (int i = 0; i < 54; i++)
{
Color col;
if (!Enum.TryParse(s.Substring(i, 1), out col))
{
throw new Exception("Invalid color");
}
count[(int)col]++;
}
}
catch (Exception e)
{
return(-1);
}
for (int i = 0; i < 6; i++)
{
if (count[i] != 9)
{
return(-1);
}
}
FaceCube fc = new FaceCube(s);
CubieCube cc = fc.toCubieCube();
return(cc.verify());
}
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// Generate a CoordCube from a CubieCube
public CoordCube(CubieCube c)
{
twist = c.getTwist();
flip = c.getFlip();
parity = c.cornerParity();
FRtoBR = c.getFRtoBR();
URFtoDLF = c.getURFtoDLF();
URtoUL = c.getURtoUL();
UBtoDF = c.getUBtoDF();
URtoDF = c.getURtoDF(); // only needed in phase2
}
/**
* Generates a random cube.
* @return A random cube in the string representation. Each cube of the cube space has the same probability.
*/
public static String randomCube()
{
CubieCube cc = new CubieCube();
Random gen = new Random();
cc.setFlip((short)gen.Next(CoordCube.N_FLIP));
cc.setTwist((short)gen.Next(CoordCube.N_TWIST));
do
{
cc.setURFtoDLB(gen.Next(CoordCube.N_URFtoDLB));
cc.setURtoBR(gen.Next(CoordCube.N_URtoBR));
} while ((cc.edgeParity() ^ cc.cornerParity()) != 0);
FaceCube fc = cc.toFaceCube();
return(fc.to_String());
}
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// Gives CubieCube representation of a faceletcube
public CubieCube toCubieCube()
{
sbyte ori;
CubieCube ccRet = new CubieCube();
for (int i = 0; i < 8; i++)
{
ccRet.cp[i] = Corner.URF; // invalidate corners
}
for (int i = 0; i < 12; i++)
{
ccRet.ep[i] = Edge.UR; // and edges
}
Color col1, col2;
foreach (Corner i in Enum.GetValues(typeof(Corner)))
{
// get the colors of the cubie at corner i, starting with U/D
for (ori = 0; ori < 3; ori++)
{
if (f[(int)cornerFacelet[(int)i][ori]] == Color.U || f[(int)cornerFacelet[(int)i][ori]] == Color.D)
{
break;
}
}
col1 = f[(int)cornerFacelet[(int)i][(ori + 1) % 3]];
col2 = f[(int)cornerFacelet[(int)i][(ori + 2) % 3]];
foreach (Corner j in Enum.GetValues(typeof(Corner)))
{
if (col1 == cornerColor[(int)j][1] && col2 == cornerColor[(int)j][2])
{
// in cornerposition i we have cornercubie j
ccRet.cp[(int)i] = j;
ccRet.co[(int)i] = (sbyte)(ori % 3);
break;
}
}
}
foreach (Edge i in Enum.GetValues(typeof(Edge)))
{
foreach (Edge j in Enum.GetValues(typeof(Edge)))
{
if (f[(int)edgeFacelet[(int)i][0]] == edgeColor[(int)j][0] &&
f[(int)edgeFacelet[(int)i][1]] == edgeColor[(int)j][1])
{
ccRet.ep[(int)i] = j;
ccRet.eo[(int)i] = 0;
break;
}
if (f[(int)edgeFacelet[(int)i][0]] == edgeColor[(int)j][1] &&
f[(int)edgeFacelet[(int)i][1]] == edgeColor[(int)j][0])
{
ccRet.ep[(int)i] = j;
ccRet.eo[(int)i] = 1;
break;
}
}
}
return(ccRet);
}
static CoordCube()
{
if (LoadPrunData())
{
return;
}
// ******************************************Phase 1 move tables*****************************************************
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// Move table for the twists of the corners
// twist < 2187 in phase 2.
// twist = 0 in phase 2.
CubieCube a = new CubieCube();
for (short i = 0; i < N_TWIST; i++)
{
a.setTwist(i);
for (int j = 0; j < 6; j++)
{
for (int k = 0; k < 3; k++)
{
a.cornerMultiply(CubieCube.moveCube[j]);
twistMove[i, 3 * j + k] = a.getTwist();
}
a.cornerMultiply(CubieCube.moveCube[j]); // 4. faceturn restores
// a
}
}
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// Move table for the flips of the edges
// flip < 2048 in phase 1
// flip = 0 in phase 2.
a = new CubieCube();
for (short i = 0; i < N_FLIP; i++)
{
a.setFlip(i);
for (int j = 0; j < 6; j++)
{
for (int k = 0; k < 3; k++)
{
a.edgeMultiply(CubieCube.moveCube[j]);
flipMove[i, 3 * j + k] = a.getFlip();
}
a.edgeMultiply(CubieCube.moveCube[j]);
// a
}
}
// ***********************************Phase 1 and 2 movetable********************************************************
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// Move table for the four UD-slice edges FR, FL, Bl and BR
// FRtoBRMove < 11880 in phase 1
// FRtoBRMove < 24 in phase 2
// FRtoBRMove = 0 for solved cube
a = new CubieCube();
for (short i = 0; i < N_FRtoBR; i++)
{
a.setFRtoBR(i);
for (int j = 0; j < 6; j++)
{
for (int k = 0; k < 3; k++)
{
a.edgeMultiply(CubieCube.moveCube[j]);
FRtoBR_Move[i, 3 * j + k] = a.getFRtoBR();
}
a.edgeMultiply(CubieCube.moveCube[j]);
}
}
// *******************************************Phase 1 and 2 movetable************************************************
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// Move table for permutation of six corners. The positions of the DBL and DRB corners are determined by the parity.
// URFtoDLF < 20160 in phase 1
// URFtoDLF < 20160 in phase 2
// URFtoDLF = 0 for solved cube.
a = new CubieCube();
for (short i = 0; i < N_URFtoDLF; i++)
{
a.setURFtoDLF(i);
for (int j = 0; j < 6; j++)
{
for (int k = 0; k < 3; k++)
{
a.cornerMultiply(CubieCube.moveCube[j]);
URFtoDLF_Move[i, 3 * j + k] = a.getURFtoDLF();
}
a.cornerMultiply(CubieCube.moveCube[j]);
}
}
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// Move table for the permutation of six U-face and D-face edges in phase2. The positions of the DL and DB edges are
// determined by the parity.
// URtoDF < 665280 in phase 1
// URtoDF < 20160 in phase 2
// URtoDF = 0 for solved cube.
a = new CubieCube();
for (short i = 0; i < N_URtoDF; i++)
{
a.setURtoDF(i);
for (int j = 0; j < 6; j++)
{
for (int k = 0; k < 3; k++)
{
a.edgeMultiply(CubieCube.moveCube[j]);
URtoDF_Move[i, 3 * j + k] = (short)a.getURtoDF();
// Table values are only valid for phase 2 moves!
// For phase 1 moves, casting to short is not possible.
}
a.edgeMultiply(CubieCube.moveCube[j]);
}
}
// **************************helper move tables to compute URtoDF for the beginning of phase2************************
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// Move table for the three edges UR,UF and UL in phase1.
a = new CubieCube();
for (short i = 0; i < N_URtoUL; i++)
{
a.setURtoUL(i);
for (int j = 0; j < 6; j++)
{
for (int k = 0; k < 3; k++)
{
a.edgeMultiply(CubieCube.moveCube[j]);
URtoUL_Move[i, 3 * j + k] = a.getURtoUL();
}
a.edgeMultiply(CubieCube.moveCube[j]);
}
}
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// Move table for the three edges UB,DR and DF in phase1.
a = new CubieCube();
for (short i = 0; i < N_UBtoDF; i++)
{
a.setUBtoDF(i);
for (int j = 0; j < 6; j++)
{
for (int k = 0; k < 3; k++)
{
a.edgeMultiply(CubieCube.moveCube[j]);
UBtoDF_Move[i, 3 * j + k] = a.getUBtoDF();
}
a.edgeMultiply(CubieCube.moveCube[j]);
}
}
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// Table to merge the coordinates of the UR,UF,UL and UB,DR,DF edges at the beginning of phase2
// for i, j <336 the six edges UR,UF,UL,UB,DR,DF are not in the
// UD-slice and the index is <20160
for (short uRtoUL = 0; uRtoUL < 336; uRtoUL++)
{
for (short uBtoDF = 0; uBtoDF < 336; uBtoDF++)
{
MergeURtoULandUBtoDF[uRtoUL, uBtoDF] = (short)CubieCube.getURtoDF(uRtoUL, uBtoDF);
}
}
// ****************************************Pruning tables for the search*********************************************
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// Pruning table for the permutation of the corners and the UD-slice edges in phase2.
// The pruning table entries give a lower estimation for the number of moves to reach the solved cube.
for (int i = 0; i < N_SLICE2 * N_URFtoDLF * N_PARITY / 2; i++)
{
Slice_URFtoDLF_Parity_Prun[i] = -1;
}
int depth = 0;
setPruning(Slice_URFtoDLF_Parity_Prun, 0, 0);
int done = 1;
while (done != N_SLICE2 * N_URFtoDLF * N_PARITY)
{
for (int i = 0; i < N_SLICE2 * N_URFtoDLF * N_PARITY; i++)
{
int parity = i % 2;
int URFtoDLF = (i / 2) / N_SLICE2;
int slice = (i / 2) % N_SLICE2;
if (((i % 2 == 0) ? (Slice_URFtoDLF_Parity_Prun[i >> 1] & 0x0f) : ((Slice_URFtoDLF_Parity_Prun[i >> 1] & 0xf0) >> 4)) == depth)
{
for (int j = 0; j < 18; j++)
{
switch (j)
{
case 3:
case 5:
case 6:
case 8:
case 12:
case 14:
case 15:
case 17:
continue;
default:
int newSlice = FRtoBR_Move[slice, j];
int newURFtoDLF = URFtoDLF_Move[URFtoDLF, j];
int newParity = parityMove[parity][j];
int index = (N_SLICE2 * newURFtoDLF + newSlice) * 2 + newParity;
if (((index % 2 == 0) ? (Slice_URFtoDLF_Parity_Prun[index >> 1] & 0x0f) : ((Slice_URFtoDLF_Parity_Prun[index >> 1] & 0xf0) >> 4)) == 0x0f)
{
setPruning(Slice_URFtoDLF_Parity_Prun, (N_SLICE2 * newURFtoDLF + newSlice) * 2 + newParity,
(sbyte)(depth + 1));
done++;
}
break;
}
}
}
}
depth++;
}
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// Pruning table for the permutation of the edges in phase2.
// The pruning table entries give a lower estimation for the number of moves to reach the solved cube.
for (int i = 0; i < N_SLICE2 * N_URtoDF * N_PARITY / 2; i++)
{
Slice_URtoDF_Parity_Prun[i] = -1;
}
depth = 0;
setPruning(Slice_URtoDF_Parity_Prun, 0, 0);
done = 1;
while (done != N_SLICE2 * N_URtoDF * N_PARITY)
{
for (int i = 0; i < N_SLICE2 * N_URtoDF * N_PARITY; i++)
{
int parity = i % 2;
int URtoDF = (i / 2) / N_SLICE2;
int slice = (i / 2) % N_SLICE2;
if (((i % 2 == 0) ? (Slice_URtoDF_Parity_Prun[i >> 1] & 0x0f) : ((Slice_URtoDF_Parity_Prun[i >> 1] & 0xf0) >> 4)) == depth)
{
for (int j = 0; j < 18; j++)
{
switch (j)
{
case 3:
case 5:
case 6:
case 8:
case 12:
case 14:
case 15:
case 17:
continue;
default:
int newSlice = FRtoBR_Move[slice, j];
int newURtoDF = URtoDF_Move[URtoDF, j];
int newParity = parityMove[parity][j];
int index = (N_SLICE2 * newURtoDF + newSlice) * 2 + newParity;
if (((index % 2 == 0) ? (Slice_URtoDF_Parity_Prun[index >> 1] & 0x0f) : ((Slice_URtoDF_Parity_Prun[index >> 1] & 0xf0) >> 4)) == 0x0f)
{
setPruning(Slice_URtoDF_Parity_Prun, (N_SLICE2 * newURtoDF + newSlice) * 2 + newParity,
(sbyte)(depth + 1));
done++;
}
break;
}
}
}
}
depth++;
}
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// Pruning table for the twist of the corners and the position (not permutation) of the UD-slice edges in phase1
// The pruning table entries give a lower estimation for the number of moves to reach the H-subgroup.
for (int i = 0; i < N_SLICE1 * N_TWIST / 2 + 1; i++)
{
Slice_Twist_Prun[i] = -1;
}
depth = 0;
setPruning(Slice_Twist_Prun, 0, (sbyte)0);
done = 1;
while (done != N_SLICE1 * N_TWIST)
{
for (int i = 0; i < N_SLICE1 * N_TWIST; i++)
{
int twist = i / N_SLICE1, slice = i % N_SLICE1;
if (((i % 2 == 0) ? (Slice_Twist_Prun[i >> 1] & 0x0f) : ((Slice_Twist_Prun[i >> 1] & 0xf0) >> 4)) == depth)
{
for (int j = 0; j < 18; j++)
{
int newSlice = FRtoBR_Move[slice * 24, j] / 24;
int newTwist = twistMove[twist, j];
int index = N_SLICE1 * newTwist + newSlice;
if (((index % 2 == 0) ? (Slice_Twist_Prun[index >> 1] & 0x0f) : ((Slice_Twist_Prun[index >> 1] & 0xf0) >> 4)) == 0x0f)
{
setPruning(Slice_Twist_Prun, N_SLICE1 * newTwist + newSlice, (sbyte)(depth + 1));
done++;
}
}
}
}
depth++;
}
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// Pruning table for the flip of the edges and the position (not permutation) of the UD-slice edges in phase1
// The pruning table entries give a lower estimation for the number of moves to reach the H-subgroup.
for (int i = 0; i < N_SLICE1 * N_FLIP / 2; i++)
{
Slice_Flip_Prun[i] = -1;
}
depth = 0;
setPruning(Slice_Flip_Prun, 0, 0);
done = 1;
while (done != N_SLICE1 * N_FLIP)
{
for (int i = 0; i < N_SLICE1 * N_FLIP; i++)
{
int flip = i / N_SLICE1, slice = i % N_SLICE1;
if (((i % 2 == 0) ? (Slice_Flip_Prun[i >> 1] & 0x0f) : ((Slice_Flip_Prun[i >> 1] & 0xf0) >> 4)) == depth)
{
for (int j = 0; j < 18; j++)
{
int newSlice = FRtoBR_Move[slice * 24, j] / 24;
int newFlip = flipMove[flip, j];
int index = N_SLICE1 * newFlip + newSlice;
if (((index % 2 == 0) ? (Slice_Flip_Prun[index >> 1] & 0x0f) : ((Slice_Flip_Prun[index >> 1] & 0xf0) >> 4)) == 0x0f)
{
setPruning(Slice_Flip_Prun, N_SLICE1 * newFlip + newSlice, (sbyte)(depth + 1));
done++;
}
}
}
}
depth++;
}
SavePrunData();
}
/**
* Computes the solver string for a given cube.
*
* @param facelets
* is the cube definition string, see {@link Facelet} for the format.
*
* @param maxDepth
* defines the maximal allowed maneuver length. For random cubes, a maxDepth of 21 usually will return a
* solution in less than 0.5 seconds. With a maxDepth of 20 it takes a few seconds on average to find a
* solution, but it may take much longer for specific cubes.
*
*@param timeOut
* defines the maximum computing time of the method in seconds. If it does not return with a solution, it returns with
* an error code.
*
* @param useSeparator
* determines if a " . " separates the phase1 and phase2 parts of the solver string like in F' R B R L2 F .
* U2 U D for example.<br>
* @return The solution string or an error code:<br>
* Error 1: There is not exactly one facelet of each colour<br>
* Error 2: Not all 12 edges exist exactly once<br>
* Error 3: Flip error: One edge has to be flipped<br>
* Error 4: Not all corners exist exactly once<br>
* Error 5: Twist error: One corner has to be twisted<br>
* Error 6: Parity error: Two corners or two edges have to be exchanged<br>
* Error 7: No solution exists for the given maxDepth<br>
* Error 8: Timeout, no solution within given time
*/
public static String solution(String facelets, int maxDepth, bool useSeparator)
{
int s;
// +++++++++++++++++++++check for wrong input +++++++++++++++++++++++++++++
int[] count = new int[6];
try
{
for (int i = 0; i < 54; i++)
{
Color col;
if (!Enum.TryParse(facelets.Substring(i, 1), out col))
{
throw new Exception("Invalid color");
}
count[(int)col]++;
}
}
catch (Exception e)
{
return("Error 1");
}
for (int i = 0; i < 6; i++)
{
if (count[i] != 9)
{
return("Error 1");
}
}
FaceCube fc = new FaceCube(facelets);
CubieCube cc = fc.toCubieCube();
if ((s = cc.verify()) != 0)
{
return("Error " + Math.Abs(s));
}
// +++++++++++++++++++++++ initialization +++++++++++++++++++++++++++++++++
CoordCube c = new CoordCube(cc);
po[0] = 0;
ax[0] = 0;
flip[0] = c.flip;
twist[0] = c.twist;
parity[0] = c.parity;
slice[0] = c.FRtoBR / 24;
URFtoDLF[0] = c.URFtoDLF;
FRtoBR[0] = c.FRtoBR;
URtoUL[0] = c.URtoUL;
UBtoDF[0] = c.UBtoDF;
minDistPhase1[1] = 1;// else failure for depth=1, n=0
int mv = 0, n = 0;
bool busy = false;
int depthPhase1 = 1;
// +++++++++++++++++++ Main loop ++++++++++++++++++++++++++++++++++++++++++
do
{
do
{
if ((depthPhase1 - n > minDistPhase1[n + 1]) && !busy)
{
if (ax[n] == 0 || ax[n] == 3)// Initialize next move
{
ax[++n] = 1;
}
else
{
ax[++n] = 0;
}
po[n] = 1;
}
else if (++po[n] > 3)
{
do
{// increment axis
if (++ax[n] > 5)
{
if (n == 0)
{
if (depthPhase1 >= maxDepth)
{
return("Error 7");
}
else
{
depthPhase1++;
ax[n] = 0;
po[n] = 1;
busy = false;
break;
}
}
else
{
n--;
busy = true;
break;
}
}
else
{
po[n] = 1;
busy = false;
}
} while (n != 0 && (ax[n - 1] == ax[n] || ax[n - 1] - 3 == ax[n]));
}
else
{
busy = false;
}
} while (busy);
// +++++++++++++ compute new coordinates and new minDistPhase1 ++++++++++
// if minDistPhase1 =0, the H subgroup is reached
mv = 3 * ax[n] + po[n] - 1;
flip[n + 1] = CoordCube.flipMove[flip[n], mv];
twist[n + 1] = CoordCube.twistMove[twist[n], mv];
slice[n + 1] = CoordCube.FRtoBR_Move[slice[n] * 24, mv] / 24;
sbyte[] table = CoordCube.Slice_Flip_Prun;
int index = CoordCube.N_SLICE1 * flip[n + 1]
+ slice[n + 1];
sbyte[] table1 = CoordCube.Slice_Twist_Prun;
int index1 = CoordCube.N_SLICE1 * twist[n + 1]
+ slice[n + 1];
minDistPhase1[n + 1] = Math.Max((index % 2 == 0) ? (table[index >> 1] & 0x0f) : ((table[index >> 1] & 0xf0) >> 4), (index1 % 2 == 0) ? (table1[index1 >> 1] & 0x0f) : ((table1[index1 >> 1] & 0xf0) >> 4));
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
if (minDistPhase1[n + 1] == 0 && n >= depthPhase1 - 5)
{
minDistPhase1[n + 1] = 10;// instead of 10 any value >5 is possible
if (n == depthPhase1 - 1 && (s = totalDepth(depthPhase1, maxDepth)) >= 0)
{
if (s == depthPhase1 ||
(ax[depthPhase1 - 1] != ax[depthPhase1] && ax[depthPhase1 - 1] != ax[depthPhase1] + 3))
{
return(useSeparator ? solutionToString(s, depthPhase1) : solutionToString(s));
}
}
}
} while (true);
}