Interactive problems are still a new topic which confuses many participants. Recently I failed to solve some of the interactive problems during contests, so I decided to practice this kind of question. For this purpose, I put together a mashup with 12 problems per 5 hours, with difficulties from Div 2 B to Div 1 C. You can upsolve the problems at your own pace.
UPD: video editorial live in 15 minutes:
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This is cool, interactive problems are my favourite! Here's one that I like a lot: B. Subway Pursuit