Problem Statement

At our company, we've set up a handful of interest-based communities so colleagues with shared interests can meet, swap ideas, run workshops, and try out different collaborative activities. There's a BA community, a QA community, a Frontend community, a DDD community, and more, alongside recreational clubs for football, video games, tennis, and yoga. You're a regular in the tennis club. You know that scheduling matches on a regular basis keeps everyone's game sharp, pulls in new colleagues, and keeps the club active. So each month you post next month's match plan and ask people to sign up. Once the sign-ups come in, you take that contestant list and do two things to put the matches together. First, the number of contestants tells you how many days the matches will need — that could be 1 or 2 days, 3 days, or more. Second, you check everyone's shared calendar to see which dates are off-limits for them. For example, say you're planning next month's (July) matches. After gathering everyon