Screencast and commentary for GCJ's leisurely qualifier (which has no time pressure).
Timestamps:
00:00 Introducing myself (where I completely forget to mention I've been an ICPC World Finals judge for 15 years)
05:41 A - Reversort
11:34 B - Moons and Umbrellas
25:34 C - Reversort Engineering
40:47 D - Median Sort
1:17:58 E - Cheating Detection
The first four problems went well. In the end, the last problem bested me; after a lot of fumbling, I ended up with a simple solution with ~30% accuracy and a more complex solution with ~60% accuracy, but 86% was needed. I had some ideas for improvement but the video was running long.
