A script handle the quiz from https://www.v2ex.com/t/309785

v2ex_309785.py

from md5 import md5

PREFIX = 'v2ex'

LETTERS = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890'

TARGET = '3bed22f7f496e84b035a996522baa7594c27c7e5718a78bfddf9012904b70eb755d67f90c8de149ead7ee674b024f38c216642030c2d54cb1dd657dd66342c99c239f3c31fd399fc052a9b7861f2073d2b9f47811dd77fd544d570c34bf5f349d110389979571714694a5054238465ca38ba26c25fb1a32b4d0a3b93666b09b3' 

prefix_md5 = md5(PREFIX).hexdigest()

hash_f = lambda s: md5(prefix_md5 + s + md5(s).hexdigest()).hexdigest()

def get_hash_str():
    for chunk in range(0, len(TARGET), 32):
        yield TARGET[chunk: chunk + 32]

base = ''

for target in get_hash_str():
    for letter in LETTERS:
        if hash_f(base+letter) == target:
            base += letter
            break

print base