An offline version could be an "Exit" advent calendar game. Now that advent has started, you might find them discounted at a local board game shop.

Note it's a single-use game.

https://boardgamegeek.com/geeksearch.php?action=search&objec...

(I don't see any reference to leetcode, but people can approach Advent of Code however they like. I'm certainly not waking up at 5:50 to race for a solution.)