Meta Hacker Cup Round 1

Good morning! Meta Hacker Cup Round 1 starts on Saturday, September 10th in under 48 hours! You're automatically registered for Round 1 if you solved at least 1 problem in the qualification round.

Important info:

• You'll qualify for Round 2 if you score at least 15 points in this round.
• You won't know whether your submissions are correct or not until after the contest, so it may be wise to solve more problems than you need in case some of your submissions end up being incorrect. Just like in the qualification round, you'll be given validation data, but there may still be cases not in validation data which could trip you up.
• The round will last 24 hours, and you may use as much of that as you would like solving problems. As usual, you may not discuss solution ideas or code until after the 24 hours is over.

T-shirt winners will be decided in Round 2, with shirts with a special badge decided in Round 3. You'll need to pass this round to be eligible for winning a shirt or advancing to the final round.

We’ve put a lot of work into these problems, and we hope you enjoy the contest. Good luck, and see you on the scoreboard!

Update: Round starts in under 10 minutes, good luck!

Update #2: Editorial