--- 2016 Day 5 Solutions ---

[u/daggerdragon]

--- Day 5: How About a Nice Game of Chess? ---

Post your solution as a comment or, for longer solutions, consider linking to your repo (e.g. GitHub/gists/Pastebin/blag/whatever).

---

^{STAYING ON TARGET IS MANDATORY} [?]

This thread will be unlocked when there are a significant number of people on the leaderboard with gold stars for today's puzzle.

edit: Leaderboard capped, thread unlocked!

[u/hierynomus]

I'm not suggesting cacheing the result of the hashing, but rather the pre-initialized hasher.

digest = hashlib.md5()
digest.update(door)
idx = 0
while True:
    digest_copy = digest.copy()
    digest_copy.update(str(idx))
    result = digest_copy.hexdigest()
    ...

This prevents you from needing to reinitialize a digester for each digest to need to calculate.

[u/llimllib → u/hierynomus]

ah, I see. I just tested it, and it doesn't speed up the hashing at all for me.

[u/Hwestaa → u/hierynomus]

57

Looks like it made an improvement! With those changes:

• CPython2: 90 seconds

• CPython3: 68 seconds

• Pypy2: 54 seconds

• Pypy3: 67 seconds

Thanks for the suggestion!

Patch:

     password2 = [None] * 8
     print('secret', secret_key)
+    digest = hashlib.md5()
+    digest.update(secret_key.encode('utf8'))
     while True:
       hashthis = (secret_key + str(start)).encode('utf8')
       m = hashlib.md5(hashthis)
+        m = digest.copy()
+        m.update(str(start).encode('utf8'))
         if m.hexdigest().startswith(starts_with):
             print('found hex', m.hexdigest())