def solve(takuzu):
'''Solve a puzzle using backtracking (also a fall back for the human solver).'''
queue = [takuzu]
# DEBUG
spots = 0
for row in range(takuzu.size):
for col in range(takuzu.size):
if not takuzu.get(row, col):
spots += 1
logging.debug('Starting backtracker, {} possibilities to try ({} spots)'.format(
2 ** spots,
spots
))
# /DEBUG
while queue:
takuzu = queue.pop()
logging.animate(takuzu)
logging.debug('Current board:\n' + str(takuzu).strip())
# Solved, we're done!
if takuzu.is_solved():
return takuzu
# If we don't have a valid solution, stop looking on this branch
if not takuzu.is_valid():
continue
# Otherwise, find one empty spot and try both possiblities
def enqueue():
for row in range(takuzu.size):
for col in range(takuzu.size):
if not takuzu.get(row, col):
for value in '01':
queue.append(takuzu.set(row, col, value))
return
enqueue()
return False
def solve(takuzu):
'''
Solve a puzzle using a hybrid model.
Start with the human solver.
Every time you get stuck, guess at a spot.
Switch back to the human solver (backtracking to step 2 on failures).
'''
queue = [takuzu]
# DEBUG
spots = 0
for row in range(takuzu.size):
for col in range(takuzu.size):
if not takuzu.get(row, col):
spots += 1
logging.debug('Starting hybrid backtracker, {} possibilities to try ({} spots)'.format(
2 ** spots,
spots
))
# /DEBUG
while queue:
takuzu = queue.pop()
# Solved, we're done!
if takuzu.is_solved():
return takuzu
# If we don't have a valid solution, stop looking on this branch
if not takuzu.is_valid():
continue
# Try to advance using the human rules until they all fail
while True:
logging.animate(takuzu)
logging.debug('Current board:\n' + str(takuzu).strip())
updated = False
for rule in RULES:
logging.debug('Trying {}'.format(rule))
next_takuzu = rule(takuzu)
if next_takuzu:
takuzu = next_takuzu
updated = True
break
if not updated:
break
# Solved, we're done!
if takuzu.is_solved():
return takuzu
# Once they've failed, find one empty spot and try both possiblities
def enqueue():
for row in range(takuzu.size):
for col in range(takuzu.size):
if not takuzu.get(row, col):
for value in '01':
queue.append(takuzu.set(row, col, value))
return
enqueue()
return False
