2018 TCO Algorithm Finals Editorials

The finalists for this round are tourist, Errichto, Um_nik, ACRush, qwerty787788, ksun48, Petr, _aid.
This round, the easy is a problem that requires a greedy observation and is simple to implement afterwards. The medium is a twist on a spanning tree problem on a 2d plane, and requires strong geometric intuition to convince yourself the solution is correct. The last problem is a tricky dp problem that can get very messy if the edge cases are not handled in a sane manner.