Task

Write a player of the Bulls and Cows game, rather than a scorer. The player should give intermediate answers that respect the scores to previous attempts.

One method is to generate a list of all possible numbers that could be the answer, then to prune the list by keeping only those numbers that would give an equivalent score to how your last guess was scored. Your next guess can be any number from the pruned list.

Either you guess correctly or run out of numbers to guess, which indicates a problem with the scoring.



Related tasks

   Bulls and cows
   Guess the number
   Guess the number/With Feedback (Player)


from itertools import permutations
from random import shuffle
 
try:
    raw_input
except:
    raw_input = input
try:
    from itertools import izip
except:
    izip = zip
 
digits = '123456789'
size = 4
 
def parse_score(score):
    score = score.strip().split(',')
    return tuple(int(s.strip()) for s in score)
 
def scorecalc(guess, chosen):
    bulls = cows = 0
    for g,c in izip(guess, chosen):
        if g == c:
            bulls += 1
        elif g in chosen:
            cows += 1
    return bulls, cows
 
choices = list(permutations(digits, size))
shuffle(choices)
answers = []
scores  = []
 
print ("Playing Bulls & Cows with %i unique digits\n" % size)
 
while True:
    ans = choices[0]
    answers.append(ans)
    #print ("(Narrowed to %i possibilities)" % len(choices))
    score = raw_input("Guess %2i is %*s. Answer (Bulls, cows)? "
                      % (len(answers), size, ''.join(ans)))
    score = parse_score(score)
    scores.append(score)
    #print("Bulls: %i, Cows: %i" % score)
    found =  score == (size, 0)
    if found:
        print ("Ye-haw!")
        break
    choices = [c for c in choices if scorecalc(c, ans) == score]
    if not choices:
        print ("Bad scoring? nothing fits those scores you gave:")
        print ('  ' +
               '\n  '.join("%s -> %s" % (''.join(an),sc)
                           for an,sc in izip(answers, scores)))
        break