standupmaths / fiveletterworda Goto Github PK

It can be renamed to fiveletterwords without breaking links! Just go to the repo settings

It's the terrible python code (provably worse than normal)
Should be
t's the terrible python code (probably worse than normal)

Sorry for mis-using the issues section here to share my results, but I couldn't resist 😄

My solution finds all 538 sets in around 50 seconds (with multi-threading on an 8-core CPU).

I'm not using fancy math (I know that's nothing to be proud of) but a few other tricks, which appear to speed things up a little:

• Valid five-word sets must use 25 out of 26 characters. Therefore, I select words containing two rare letters
  (x and / or q, there are only 315 such words) and use only them as 'seed words'. Then I only have to find four
  more words per seed word. Because every valid set must contain either an x and / or a q I can't miss a set.

• Initially, I build 26 sets (one for each letter) containing all words that include the particular letter. This
  helps in efficiently removing invalid word candidates later on.

• The search function works recursively and removes invalid words from the list of candidates for deeper recursion
  levels (using the words-by-letter sets mentioned above). This way the search can terminate early once there are no more word candidates left.

The code is pretty simple (~150 lines including comments), however I used kotlin as programming language instead of python.

I left a YT comment, but apparently YT doesn't like me and just deleted it. Brute force solution with bit twiddling and avoiding duplicate work runs in <1 min for the original word list on my computer and finds all 538 sets.
https://github.com/ahouts/five-letter-words