labyrinth

gistfile1.py

import Queue

queue = Queue.Queue()
valueSet = set()
valueProc = [(lambda x: x/2+7, 1), (lambda x: (x+7)/2, 0), (lambda x: x*3-5, 3),(lambda x: (x-5)*3, 2)]
valueTry = [(lambda x: (x-5), 2), (lambda x: x*3, 3)]

def check(value, state):
    for f, s in valueTry:
        if not state == s:
            if f(value) == 2012:
                return True
    return False

def run(((value, state), l)):
    if check(value, state) == True:
        print "find it"
        print "2011", "-->"
        for step in l:
            print step, "-->"
        print "2012"
        exit()
    else:
        for index, (f, s) in enumerate(valueProc):
            if not state == s:
                o = (f(value), index)
                if o in valueSet:
                    continue
                valueSet.add(o)
                a = list(l)
                a.append(o)
                queue.put((o, a))

def main():
    valueSet.add((2011+7, 0))
    valueSet.add((2011/2, 1))
    queue.put(((2011+7, 0), [(2018, 0)]))
    queue.put(((2011/2, 1), [(1005, 1)]))

    while not queue.empty():
        run(queue.get())

if __name__ == "__main__":
    main()

"""
结果:
find it
2011 -->
(1005, 1) -->
(506, 1) -->
(256, 1) -->
(131, 1) -->
(69, 1) -->
(202, 2) -->
(601, 2) -->
(304, 1) -->
(897, 3) -->
(2676, 3) -->
(1345, 0) -->
(4020, 3) -->
(2017, 0) -->
2012
"""