Hi all. I want to invite you to HourRank 9. The contest will take place tomorrow (exact time) on HackerRank. There are three problems to be solved in one hour.

For this round I wrote the problems. I hope you find them interesting! wanbo tested them, and other contributors (pre-solving, suggestions, technical help, etc.) are malcolm, satyaki3794, and Shafaet. Thank you for all your help!

The top 10 will get awesome HackerRank t-shirts. Editorials will be available at the end. Good luck and have fun!

Update: Score distribution : 30-50-80