play24.py

#!/usr/bin/python -tt

import sys
import re
import itertools  # http://docs.python.org/library/itertools.html#itertools.combinations

# GENERATOR FOR TEST PATTERNS
def testPatterns(args):
    patterns = ['%f+%f+%f+%f',
                '%f-%f-%f-%f',
                '%f*%f*%f*%f',
                '%f/%f/%f/%f',
                '(%f+%f)*(%f+%f)',
                '(%f-%f)*(%f-%f)',
                '(%f+%f)*%f*%f',
                '(%f-%f)*%f*%f',
                '(%f-%f)*%f+%f',
                '(%f-%f)*%f-%f',
                '%f*(%f+%f)+%f',
                '%f*(%f-%f)-%f',
                '%f*(%f-%f)+%f',
                '%f*(%f+%f)-%f',
                '%f+(%f/%f)*%f',
                '(%f/%f+%f)*%f']
    for pattern in patterns:
        yield pattern % (float(args[0]), float(args[1]), float(args[2]), float(args[3]))

# GENERATE ALL POSSIBLE COMBINATIONS FROM ARGS PROVIDED
# Code based on the following documetion
# http://docs.python.org/library/itertools.html#itertools.combinations
def combinations(iterable, r):
    pool = tuple(iterable)
    n = len(pool)
    for indices in itertools.permutations(range(n), r):
        yield tuple(pool[i] for i in indices)

# GAMEPLAY
def play24(ints):
    target = 24
    for int in ints:
        print int
    print "thinking..."

    for combo in combinations(ints, 4):
        #print "COMBO:", combo
        for test in testPatterns(combo):
            #print test, eval(test)
            if eval(test) == target:
                print "FOUND: ", test
                return
    print "no patterns result in %f" % target
    

def main():
    ints = sys.argv[1:]
    
    # IF NO ARGS PASSED, DEFINE A DEFAULT SET
    if not ints:
        print "usage: [--int 1-10][--int 1-10][--int 1-10][--int 1-10]";
        ints = [4,10,4,2]
    
    # MAKE SURE THERE ARE NO 0'S SO WE DON'T GET A DENOMINATOR ERROR
    for i in ints:
        if(i == 0): 
            print "no 0's please"
            sys.exit(1)
    
    # MAKE SURE WE'VE GOT 4 AND ONLY 4 ARGUMENTS  
    if len(ints) != 4:
        print "only 4 arguments, please";
        sys.exit(1)
        
    play24(ints)
    print "end"

# This is the standard boilerplate that calls the main() function.
if __name__ == '__main__':
  main()