RosettaCodeData/Task/Stable-marriage-problem/Python/stable-marriage-problem.py

104 lines
4.4 KiB
Python

import copy
guyprefers = {
'abe': ['abi', 'eve', 'cath', 'ivy', 'jan', 'dee', 'fay', 'bea', 'hope', 'gay'],
'bob': ['cath', 'hope', 'abi', 'dee', 'eve', 'fay', 'bea', 'jan', 'ivy', 'gay'],
'col': ['hope', 'eve', 'abi', 'dee', 'bea', 'fay', 'ivy', 'gay', 'cath', 'jan'],
'dan': ['ivy', 'fay', 'dee', 'gay', 'hope', 'eve', 'jan', 'bea', 'cath', 'abi'],
'ed': ['jan', 'dee', 'bea', 'cath', 'fay', 'eve', 'abi', 'ivy', 'hope', 'gay'],
'fred': ['bea', 'abi', 'dee', 'gay', 'eve', 'ivy', 'cath', 'jan', 'hope', 'fay'],
'gav': ['gay', 'eve', 'ivy', 'bea', 'cath', 'abi', 'dee', 'hope', 'jan', 'fay'],
'hal': ['abi', 'eve', 'hope', 'fay', 'ivy', 'cath', 'jan', 'bea', 'gay', 'dee'],
'ian': ['hope', 'cath', 'dee', 'gay', 'bea', 'abi', 'fay', 'ivy', 'jan', 'eve'],
'jon': ['abi', 'fay', 'jan', 'gay', 'eve', 'bea', 'dee', 'cath', 'ivy', 'hope']}
galprefers = {
'abi': ['bob', 'fred', 'jon', 'gav', 'ian', 'abe', 'dan', 'ed', 'col', 'hal'],
'bea': ['bob', 'abe', 'col', 'fred', 'gav', 'dan', 'ian', 'ed', 'jon', 'hal'],
'cath': ['fred', 'bob', 'ed', 'gav', 'hal', 'col', 'ian', 'abe', 'dan', 'jon'],
'dee': ['fred', 'jon', 'col', 'abe', 'ian', 'hal', 'gav', 'dan', 'bob', 'ed'],
'eve': ['jon', 'hal', 'fred', 'dan', 'abe', 'gav', 'col', 'ed', 'ian', 'bob'],
'fay': ['bob', 'abe', 'ed', 'ian', 'jon', 'dan', 'fred', 'gav', 'col', 'hal'],
'gay': ['jon', 'gav', 'hal', 'fred', 'bob', 'abe', 'col', 'ed', 'dan', 'ian'],
'hope': ['gav', 'jon', 'bob', 'abe', 'ian', 'dan', 'hal', 'ed', 'col', 'fred'],
'ivy': ['ian', 'col', 'hal', 'gav', 'fred', 'bob', 'abe', 'ed', 'jon', 'dan'],
'jan': ['ed', 'hal', 'gav', 'abe', 'bob', 'jon', 'col', 'ian', 'fred', 'dan']}
guys = sorted(guyprefers.keys())
gals = sorted(galprefers.keys())
def check(engaged):
inverseengaged = dict((v,k) for k,v in engaged.items())
for she, he in engaged.items():
shelikes = galprefers[she]
shelikesbetter = shelikes[:shelikes.index(he)]
helikes = guyprefers[he]
helikesbetter = helikes[:helikes.index(she)]
for guy in shelikesbetter:
guysgirl = inverseengaged[guy]
guylikes = guyprefers[guy]
if guylikes.index(guysgirl) > guylikes.index(she):
print("%s and %s like each other better than "
"their present partners: %s and %s, respectively"
% (she, guy, he, guysgirl))
return False
for gal in helikesbetter:
girlsguy = engaged[gal]
gallikes = galprefers[gal]
if gallikes.index(girlsguy) > gallikes.index(he):
print("%s and %s like each other better than "
"their present partners: %s and %s, respectively"
% (he, gal, she, girlsguy))
return False
return True
def matchmaker():
guysfree = guys[:]
engaged = {}
guyprefers2 = copy.deepcopy(guyprefers)
galprefers2 = copy.deepcopy(galprefers)
while guysfree:
guy = guysfree.pop(0)
guyslist = guyprefers2[guy]
gal = guyslist.pop(0)
fiance = engaged.get(gal)
if not fiance:
# She's free
engaged[gal] = guy
print(" %s and %s" % (guy, gal))
else:
# The bounder proposes to an engaged lass!
galslist = galprefers2[gal]
if galslist.index(fiance) > galslist.index(guy):
# She prefers new guy
engaged[gal] = guy
print(" %s dumped %s for %s" % (gal, fiance, guy))
if guyprefers2[fiance]:
# Ex has more girls to try
guysfree.append(fiance)
else:
# She is faithful to old fiance
if guyslist:
# Look again
guysfree.append(guy)
return engaged
print('\nEngagements:')
engaged = matchmaker()
print('\nCouples:')
print(' ' + ',\n '.join('%s is engaged to %s' % couple
for couple in sorted(engaged.items())))
print()
print('Engagement stability check PASSED'
if check(engaged) else 'Engagement stability check FAILED')
print('\n\nSwapping two fiances to introduce an error')
engaged[gals[0]], engaged[gals[1]] = engaged[gals[1]], engaged[gals[0]]
for gal in gals[:2]:
print(' %s is now engaged to %s' % (gal, engaged[gal]))
print()
print('Engagement stability check PASSED'
if check(engaged) else 'Engagement stability check FAILED')