[Level 21]
We used to play this game when we were kids
When I had no idea what to do, I looked backwards.
再加一个package.pack文件，就是[Level 21]了。没想出来，依旧百度谷歌。
游戏指的是击鼓传花，我们要做的是根据数据内容判断使用zlib或bz2解压package.pack文件，并对每一步骤进行标记。
import zlib,bz2
f = open('package.pack','rb').read()
while True:
if f.startswith(b'BZ'):
f = bz2.decompress(f)
elif f.startswith(b'x\x9c'):
f = zlib.decompress(f)
elif f.endswith(b'\x9cx'):
f = f[::-1]
else:
break
最终解出来的数据d是b'sgol ruoy ta kool'，即look at your logs，result是copper，22关的钥匙，[Level 22]
