A-M baby

Task/24-game-Solve/Python/24-game-solve.py

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+'''
+ The 24 Game Player
+
+ Given any four digits in the range 1 to 9, which may have repetitions,
+ Using just the +, -, *, and / operators; and the possible use of
+ brackets, (), show how to make an answer of 24.
+
+ An answer of "q"  will quit the game.
+ An answer of "!"  will generate a new set of four digits.
+ An answer of "!!" will ask you for a new set of four digits.
+ An answer of "?"  will compute an expression for the current digits.
+
+ Otherwise you are repeatedly asked for an expression until it evaluates to 24
+
+ Note: you cannot form multiple digit numbers from the supplied digits,
+ so an answer of 12+12 when given 1, 2, 2, and 1 would not be allowed.
+
+'''
+
+from   __future__ import division, print_function
+from   itertools  import permutations, combinations, product, \
+                         chain
+from   pprint     import pprint as pp
+from   fractions  import Fraction as F
+import random, ast, re
+import sys
+
+if sys.version_info[0] < 3:
+    input = raw_input
+    from itertools import izip_longest as zip_longest
+else:
+    from itertools import zip_longest
+
+
+def choose4():
+    'four random digits >0 as characters'
+    return [str(random.randint(1,9)) for i in range(4)]
+
+def ask4():
+    'get four random digits >0 from the player'
+    digits = ''
+    while len(digits) != 4 or not all(d in '123456789' for d in digits):
+        digits = input('Enter the digits to solve for: ')
+        digits = ''.join(digits.strip().split())
+    return list(digits)
+
+def welcome(digits):
+    print (__doc__)
+    print ("Your four digits: " + ' '.join(digits))
+
+def check(answer, digits):
+    allowed = set('() +-*/\t'+''.join(digits))
+    ok = all(ch in allowed for ch in answer) and \
+         all(digits.count(dig) == answer.count(dig) for dig in set(digits)) \
+         and not re.search('\d\d', answer)
+    if ok:
+        try:
+            ast.parse(answer)
+        except:
+            ok = False
+    return ok
+
+def solve(digits):
+    """\
+    >>> for digits in '3246 4788 1111 123456 1127 3838'.split():
+            solve(list(digits))
+
+
+    Solution found: 2 + 3 * 6 + 4
+    '2 + 3 * 6 + 4'
+    Solution found: ( 4 + 7 - 8 ) * 8
+    '( 4 + 7 - 8 ) * 8'
+    No solution found for: 1 1 1 1
+    '!'
+    Solution found: 1 + 2 + 3 * ( 4 + 5 ) - 6
+    '1 + 2 + 3 * ( 4 + 5 ) - 6'
+    Solution found: ( 1 + 2 ) * ( 1 + 7 )
+    '( 1 + 2 ) * ( 1 + 7 )'
+    Solution found: 8 / ( 3 - 8 / 3 )
+    '8 / ( 3 - 8 / 3 )'
+    >>> """
+    digilen = len(digits)
+    # length of an exp without brackets
+    exprlen = 2 * digilen - 1
+    # permute all the digits
+    digiperm = sorted(set(permutations(digits)))
+    # All the possible operator combinations
+    opcomb   = list(product('+-*/', repeat=digilen-1))
+    # All the bracket insertion points:
+    brackets = ( [()] + [(x,y)
+                         for x in range(0, exprlen, 2)
+                         for y in range(x+4, exprlen+2, 2)
+                         if (x,y) != (0,exprlen+1)]
+                 + [(0, 3+1, 4+2, 7+3)] ) # double brackets case
+    for d in digiperm:
+        for ops in opcomb:
+            if '/' in ops:
+                d2 = [('F(%s)' % i) for i in d] # Use Fractions for accuracy
+            else:
+                d2 = d
+            ex = list(chain.from_iterable(zip_longest(d2, ops, fillvalue='')))
+            for b in brackets:
+                exp = ex[::]
+                for insertpoint, bracket in zip(b, '()'*(len(b)//2)):
+                    exp.insert(insertpoint, bracket)
+                txt = ''.join(exp)
+                try:
+                    num = eval(txt)
+                except ZeroDivisionError:
+                    continue
+                if num == 24:
+                    if '/' in ops:
+                        exp = [ (term if not term.startswith('F(') else term[2])
+                               for term in exp ]
+                    ans = ' '.join(exp).rstrip()
+                    print ("Solution found:",ans)
+                    return ans
+    print ("No solution found for:", ' '.join(digits))
+    return '!'
+
+def main():
+    digits = choose4()
+    welcome(digits)
+    trial = 0
+    answer = ''
+    chk = ans = False
+    while not (chk and ans == 24):
+        trial +=1
+        answer = input("Expression %i: " % trial)
+        chk = check(answer, digits)
+        if answer == '?':
+            solve(digits)
+            answer = '!'
+        if answer.lower() == 'q':
+            break
+        if answer == '!':
+            digits = choose4()
+            trial = 0
+            print ("\nNew digits:", ' '.join(digits))
+            continue
+        if answer == '!!':
+            digits = ask4()
+            trial = 0
+            print ("\nNew digits:", ' '.join(digits))
+            continue
+        if not chk:
+            print ("The input '%s' was wonky!" % answer)
+        else:
+            if '/' in answer:
+                # Use Fractions for accuracy in divisions
+                answer = ''.join( (('F(%s)' % char) if char in '123456789' else char)
+                                  for char in answer )
+            ans = eval(answer)
+            print (" = ", ans)
+            if ans == 24:
+                print ("Thats right!")
+    print ("Thank you and goodbye")
+
+main()