int Solver::Search2(
int cornerPermutation,
int nonMiddleSliceEdgePermutation,
int middleSliceEdgePermutation,
int depth)
{
int cost, totalCost;
int move;
int power, powerLimit;
int cornerPermutation2;
int nonMiddleSliceEdgePermutation2;
int middleSliceEdgePermutation2;
int result;
// Compute cost estimate to goal state
cost = Phase2Cost(
cornerPermutation,
nonMiddleSliceEdgePermutation,
middleSliceEdgePermutation); // h
if (cost == 0) // Solution found...
{
solutionLength2 = depth; // Save phase 2 solution length
if (solutionLength1 + solutionLength2 < minSolutionLength)
minSolutionLength = solutionLength1 + solutionLength2;
PrintSolution();
return FOUND;
}
// See if node should be expanded
totalCost = depth + cost; // g + h
if (totalCost <= threshold2) // Expand node
{
// No point in continuing to search for solutions of equal or greater
// length than the current best solution
if (solutionLength1 + depth >= minSolutionLength-1) return ABORT;
for (move = Cube::Move::R; move <= Cube::Move::B; move++)
{
if (Disallowed(move, solutionMoves2, depth)) continue;
cornerPermutation2 = cornerPermutation;
nonMiddleSliceEdgePermutation2 = nonMiddleSliceEdgePermutation;
middleSliceEdgePermutation2 = middleSliceEdgePermutation;
solutionMoves2[depth] = move;
powerLimit = 4;
if (move != Cube::Move::U && move != Cube::Move::D) powerLimit=2;
for (power = 1; power < powerLimit; power++)
{
cornerPermutation2 =
cornerPermutationMoveTable[cornerPermutation2][move];
nonMiddleSliceEdgePermutation2 =
nonMiddleSliceEdgePermutationMoveTable[nonMiddleSliceEdgePermutation2][move];
middleSliceEdgePermutation2 =
middleSliceEdgePermutationMoveTable[middleSliceEdgePermutation2][move];
solutionPowers2[depth] = power;
nodes2++;
// Apply the move
if (result = Search2(
cornerPermutation2,
nonMiddleSliceEdgePermutation2,
middleSliceEdgePermutation2, depth+1))
return result;
}
}
}
else // Maintain minimum cost exceeding threshold
{
if (totalCost < newThreshold2)
newThreshold2 = totalCost;
}
return NOT_FOUND;
}
int Solver::Search2(
int cornerPermutation,
int nonMiddleSliceEdgePermutation,
int middleSliceEdgePermutation,
int depth)
{
int cost, totalCost;
int move;
int power, powerLimit;
int cornerPermutation2;
int nonMiddleSliceEdgePermutation2;
int middleSliceEdgePermutation2;
int result;
cost = Phase2Cost(
cornerPermutation,
nonMiddleSliceEdgePermutation,
middleSliceEdgePermutation);
if (cost == 0)
{
solutionLength2 = depth;
if (solutionLength1 + solutionLength2 < minSolutionLength)
minSolutionLength = solutionLength1 + solutionLength2;
PrintSolution();
return FOUND;
}
if (cost < 2)
Window->ProgressStep(1);
totalCost = depth + cost;
if (totalCost <= threshold2)
{
if (solutionLength1 + depth >= minSolutionLength-1) return ABORT;
for (move = Cube::R; move <= Cube::B; move++)
{
if (Disallowed(move, solutionMoves2, depth)) continue;
cornerPermutation2 = cornerPermutation;
nonMiddleSliceEdgePermutation2 = nonMiddleSliceEdgePermutation;
middleSliceEdgePermutation2 = middleSliceEdgePermutation;
solutionMoves2[depth] = move;
powerLimit = 4;
if (move != Cube::U && move != Cube::D) powerLimit=2;
for (power = 1; power < powerLimit; power++)
{
cornerPermutation2 =
cornerPermutationMoveTable
[cornerPermutation2][move];
nonMiddleSliceEdgePermutation2 =
nonMiddleSliceEdgePermutationMoveTable
[nonMiddleSliceEdgePermutation2][move];
middleSliceEdgePermutation2 =
middleSliceEdgePermutationMoveTable
[middleSliceEdgePermutation2][move];
solutionPowers2[depth] = power;
nodes2++;
if ((result = Search2(
cornerPermutation2,
nonMiddleSliceEdgePermutation2,
middleSliceEdgePermutation2, depth+1)))
return result;
}
}
}
else
{
if (totalCost < newThreshold2)
newThreshold2 = totalCost;
}
return NOT_FOUND;
}
int Solver::Search1(int twist, int flip, int choice, int depth)
{
int cost, totalCost;
int move;
int power;
int twist2, flip2, choice2;
int result;
// Compute cost estimate to phase 1 goal state
cost = Phase1Cost(twist, flip, choice); // h
if (cost == 0) // Phase 1 solution found...
{
solutionLength1 = depth; // Save phase 1 solution length
// We need an appropriately initialized cube in order
// to begin phase 2. First, create a new cube that
// is a copy of the initial scrambled cube. Then we
// apply the phase 1 move sequence to that cube. The
// phase 2 search can then determine the initial
// phase 2 coordinates (corner, edge, and slice
// permutation) from this cube.
//
// Note: No attempt is made to merge moves of the same
// face adjacent to the phase 1 & phase 2 boundary since
// the shorter sequence will quickly be found.
KociembaCube phase2Cube = cube;
for (int i = 0; i < solutionLength1; i++)
{
for (power = 0; power < solutionPowers1[i]; power++)
phase2Cube.ApplyMove(solutionMoves1[i]);
}
// Invoke Phase 2
(void)Solve2(phase2Cube);
}
// See if node should be expanded
totalCost = depth + cost; // g + h
if (totalCost <= threshold1) // Expand node
{
// If this happens, we should have found the
// optimal solution at this point, so we
// can exit indicating such. Note: the first
// complete solution found in phase1 is optimal
// due to it being an addmissible IDA* search.
if (depth >= minSolutionLength-1 || minSolutionLength < 24)
return OPTIMUM_FOUND;
for (move = Cube::Move::R; move <= Cube::Move::B; move++)
{
if (Disallowed(move, solutionMoves1, depth)) continue;
twist2 = twist;
flip2 = flip;
choice2 = choice;
solutionMoves1[depth] = move;
for (power = 1; power < 4; power++)
{
solutionPowers1[depth] = power;
twist2 = twistMoveTable[twist2][move];
flip2 = flipMoveTable[flip2][move];
choice2 = choiceMoveTable[choice2][move];
nodes1++;
// Apply the move
if (result = Search1(twist2, flip2, choice2, depth+1))
return result;
}
}
}
else // Maintain minimum cost exceeding threshold
{
if (totalCost < newThreshold1)
newThreshold1 = totalCost;
}
return NOT_FOUND;
}
int Solver::Search1(int twist, int flip, int choice, int depth)
{
int cost, totalCost;
int move;
int power;
int twist2, flip2, choice2;
int result;
cost = Phase1Cost(twist, flip, choice);
if (cost == 0)
{
solutionLength1 = depth;
KociembaCube phase2Cube = cube;
for (int i = 0; i < solutionLength1; i++)
{
for (power = 0; power < solutionPowers1[i]; power++)
phase2Cube.ApplyMove(solutionMoves1[i]);
}
(void)Solve2(phase2Cube);
if(stopped) return ABORT;
}
totalCost = depth + cost;
if (totalCost <= threshold1)
{
if (depth >= minSolutionLength-1)
return OPTIMUM_FOUND;
for (move = Cube::R; move <= Cube::B; move++)
{
if (Disallowed(move, solutionMoves1, depth)) continue;
twist2 = twist;
flip2 = flip;
choice2 = choice;
solutionMoves1[depth] = move;
for (power = 1; power < 4; power++)
{
solutionPowers1[depth] = power;
twist2 = twistMoveTable[twist2][move];
flip2 = flipMoveTable[flip2][move];
choice2 = choiceMoveTable[choice2][move];
if ((result =
Search1(twist2, flip2, choice2, depth+1)))
return result;
}
}
}
else
{
if (totalCost < newThreshold1)
newThreshold1 = totalCost;
}
return NOT_FOUND;
}