depot - monorepo for the virus lounge

Age	Commit message (Collapse)	Author	Files	Lines
2020-11-23	Update BFS impls	William Carroll	1	-1/+1
	I've subtly been implementing breadth-first traversals in graphs incorrectly. The change is subtle, but updating `seen` needs to happen immediately after queuing an item. The results will remain the same, but the runtimes will differ dramatically. I didn't notice this until I attempted to complete LeetCode's "count islands" challenge, and LeetCode rejected my solution because it could not finish before timing out. After looking at other candidates' solutions and comparing them to mine, I couldn't see any difference... except for this subtle difference. This SO answer provides a helpful explanation: https://stackoverflow.com/questions/45623722/marking-node-as-visited-on-bfs-when-dequeuing The take-away lesson here is to always call `seen.add(..)` immediately after enqueuing.
2020-11-20	Solve "count islands" problem	William Carroll	1	-0/+53
	This morning, I attended the "Interview Club" and was asked this question by the interviewer in front of ~20 FTEs. While I struggled to fully solve it during the abridged (i.e. 20 minute) timeslot, I completed the problem afterwards. Here is my solution.