Thursday, May 2, 2019

A close to third week

TopCoder SRM 753 opened the Mar 18 - Mar 24 week in competitive programming (problems, results, top 5 on the left, analysis). Just ecnerwal and mnbvmar solved all three problems, and ecnerwal was so much faster that the challenge phase did not really matter. Congratulations on the victory!

AtCoder Grand Contest 032 took place on Saturday (problems, results, top 5 on the left, analysis). ksun48 solved problem F in just 30 minutes, and tourist solved problem E in just 15 minutes, but nobody was able to solve both during the round. Therefore the advantage went to contestants who went for F, and ksun48 was by far the fastest of those. Well done!

The hardest problem F had a very simple-looking statement. We pick n independent uniformly random points on a circle, and then find two points the (circular/angular) distance between which is as close to 1/3 of the circle as possible. What is the expected value of the difference between that distance, expressed as a fraction of the circle, and 1/3? n is up to 106, and you need to compute the answer using division modulo 109+7.

Open Cup 2018-19 Grand Prix of Moscow was the last Open Cup round before the ICPC 2019 World Finals (results, top 5 on the left). Moscow SU team was setting the problems, but many other top ICPC teams competed. Three future gold medalists appear on the screenshot on the left :) Team Past Glory was head and shoulders above everybody, being the only team to finish all 13 problems, and doing it in just 3:40. Amazing dominance!

Thanks for reading, and check back for more.

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