As requested, here's an attempt at a richer screencast for SRM 491 - this one also has a side-cam view at myself and my table. I'm afraid it doesn't make the screencast much more interesting, but probably it becomes a bit more funny, and the psychological experiment of working while knowingly being recorded was definitely interesting. Feels a bit like creating the big event atmosphere at home :) Since the file turned out to be 3.2G, the only feasible way to distribute it seems to be via: Torrent.
The highlight of that SRM was the failing min-cost-max-flow solution for the hard problem, which was even one of the intended solutions by the judges. Luckily, there was another greedy solution that worked much more quickly. I went this road, but in the opposite direction: my first solution was greedy, then I wrote a stress test against a stupid solution and found it didn't work, couldn't figure out how to fix it and then came up with the min-cost-max-flow solution which I've resubmitted and which failed systest due to timeout. After the match, the logical question was: why did I choose writing min-cost-max-flow instead of fixing the greedy solution? I think that the answer is that programming contests teach us to look for a 'beautifully fitting' solution. When I saw the reduction to min-cost-max-flow, it looked like something the author of the problem had in mind, and I gave it no second thought.
Here are other screencasts of 2010, just for the record.
SRM 461: Torrent
SRM 476: Torrent
SRM 480: Torrent
SRM 485: Torrent
SRM 486: Torrent
The highlight of that SRM was the failing min-cost-max-flow solution for the hard problem, which was even one of the intended solutions by the judges. Luckily, there was another greedy solution that worked much more quickly. I went this road, but in the opposite direction: my first solution was greedy, then I wrote a stress test against a stupid solution and found it didn't work, couldn't figure out how to fix it and then came up with the min-cost-max-flow solution which I've resubmitted and which failed systest due to timeout. After the match, the logical question was: why did I choose writing min-cost-max-flow instead of fixing the greedy solution? I think that the answer is that programming contests teach us to look for a 'beautifully fitting' solution. When I saw the reduction to min-cost-max-flow, it looked like something the author of the problem had in mind, and I gave it no second thought.
Here are other screencasts of 2010, just for the record.
SRM 461: Torrent
SRM 476: Torrent
SRM 480: Torrent
SRM 485: Torrent
SRM 486: Torrent
Hi, Petr
ReplyDeletePlease help me. I can not access the links.
I've fixed the links - please tell if they don't work now.
ReplyDeleteThank you so much for your help :)
ReplyDeleteThanks for sharing but I'm stuck on 22% on the SRM-491 - is it possible for you to seed some more? And congrats on the latest win SRM-500! You're a big inspiration
ReplyDeleteI'm seeding right now - and somebody is downloading, at 56%. Cound you confirm that everything is fine now?
ReplyDeleteUnfortunately my client still says "Seeds: 0 (0)"
ReplyDeleteWhat's your client's IP and port? I can try to manually "Add Peer".
ReplyDeleteHmmm, tricky ... I think my IP is 85.225.243.159 and port should be 6881 :)
ReplyDeleteIt's downloading now! Seeds: 1, Peers: 1, Availability: 1,029 :)
ReplyDeleteTurns out the key to downloading was patience :) A few weeks was all it needed... now just add some popcorn and I'm all set! Great match again - 502, you're totally awesome
ReplyDeleteYour 2.0 screencast was very interesting. I enjoyed it so much, and it taught me a lot.
ReplyDeleteHope you can make it again in the next SRM :)
Hii petr I am unable to access any of these links can you fix it.
ReplyDeleteThanks you
Torrents should work, I've removed the rest since I no longer maintain my own HTTP server as you've noticed.
ReplyDelete