def solveBoard(board):
global numUnique, printResult, checkUnique, checkUnique
def assumeBoard(printBoard):
for v in checkAssumps:
cnf.assume(-v)
row = 0
col = 0
for b in board:
if printBoard:
sys.stdout.write(b)
if b == ".":
pass
else:
i = -1
if N < 10:
i = int(b) - 1
else:
i = ord(b) - ord("A")
# print '(%d,%d) = i = %d' % (row,col,i)
cnf.assume(p[i][row][col])
col += 1
if col == N:
col = 0
row += 1
if row == N:
break
if printBoard:
sys.stdout.write("\n")
assumeBoard(printResult)
result = cnf.solve()
assert result == cnf.RESULT_SAT
if printResult:
showBoard(board)
if checkUnique:
v = cnf.newVar("uniq")
c = [-v]
for j in range(0, N):
for k in range(0, N):
for i in range(0, N):
if cnf.assignment(p[i][j][k]):
c.append(-p[i][j][k])
cnf.addClause("uniq", c)
assumeBoard(False)
cnf.assume(v)
checkAssumps.append(v)
result = cnf.solve()
if result == cnf.RESULT_SAT:
print "non-unique board"
showBoard(board)
return False
elif result == cnf.RESULT_UNSAT:
numUnique += 1
return True
def __init__(self, name, rows, cols):
self.tbl = {}
self.rows = rows
self.cols = cols
for r in rows:
self.tbl[r] = {}
clause = []
for c in cols:
self.tbl[r][c] = cnf.newVar(name)
clause.append( self.tbl[r][c] )
cnf.addClause('>=1', clause)
for r in rows:
for c1 in cols:
for c2 in cols:
if c1 != c2:
cnf.addClause('<=1', [-self.tbl[r][c1], -self.tbl[r][c2]])
def entry(row, col):
assert row in self.rows
assert col in self.cols
return self.tbl[row][col]
def setup():
"""
Sets up universal sudoku constraints. Nothing set up here is specific to the
actual board being solved.
"""
cnf.init()
cnf.pico.picosat_set_seed(0)
# cnf.pico.picosat_set_global_default_phase(0) # 1361274
cnf.pico.picosat_set_global_default_phase(1) # 1353908
# create vars
for i in range(0, N):
p[i] = {}
for j in range(0, N):
p[i][j] = {}
for k in range(0, N):
p[i][j][k] = cnf.newVar("[%d][%d] = %d" % (j, k, i))
# must choose at least one possibility per square
for j in range(0, N):
for k in range(0, N):
clause = []
for i in range(0, N):
clause.append(p[i][j][k])
cnf.addClause(">=1", clause)
# must choose at most one possibility per square
for j in range(0, N):
for k in range(0, N):
for i in range(0, N):
for l in range(0, N):
if i != l:
cnf.addClause("<=1", [-p[i][j][k], -p[l][j][k]])
# columns have 1-9 at most once
for i in range(0, N):
for r in range(0, N):
for c in range(0, N):
for r2 in range(0, N):
if r2 != r:
cnf.addClause("col_val", [-p[i][r][c], -p[i][r2][c]])
# rows have 1-9 at most once
for i in range(0, N):
for r in range(0, N):
for c in range(0, N):
for c2 in range(0, N):
if c2 != c:
cnf.addClause("row_val", [-p[i][r][c], -p[i][r][c2]])
# 3x3 grids have 1-9 at most once
for s in range(0, N / Sq):
for t in range(0, N / Sq):
for r in range(s * (N / Sq), (s + 1) * (N / Sq)):
for c in range(t * (N / Sq), (t + 1) * (N / Sq)):
for r2 in range(s * (N / Sq), (s + 1) * (N / Sq)):
for c2 in range(t * (N / Sq), (t + 1) * (N / Sq)):
# comment this out to see if your python doesn't suck.
# it doesn't error iff it sucks
for i in range(0, N):
if r != r2 and c != c2:
# print "%d %d %d -- %d %d %d" % (i,r,c, i,r2,c2)
cnf.addClause("3x3", [-p[i][r][c], -p[i][r2][c2]])
