Sunday, January 28, 2018

A TopCoder week

TopCoder SRM 728 was this week's contest (problems, results, top 5 on the left, analysis, my screencast). The hard problem was a relatively straightforward application of the Burnside's lemma, which I described in this blog more than 9 (!) years ago. The easy problem allowed a ton of completely different correct approaches, and thus in a sense was more interesting: you are given 50 integers, each up to a billion. In one step, you can take any integer that is greater than 1 and divide it by 2. If it was odd, you can choose whether to round up or down. What is the smallest number of steps required to make all integers equal?

I've also just realized that I forgot to cover the previous SRM, TopCoder SRM 727 which took place two weeks ago very early in the morning (problems, results, top 5 on the left, analysis). lych_cys, participating in Division 1 for the first time, has squeezed the victory during the challenge phase from wxh010910, who was doing only his third Division 1 round himself, while the rest of the pack was more than 100 points behind. Congratulations to the winning newcomers!

Thanks for reading, and check back next week!

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