- Thoughts.
- You are given a highly flexible representation of the placement of the dominoes, but essentially all you need is a “place them vertically” or “place two horizontally” column. Convert to that first.
- when the foreground is horizontal
- Verticals have only one way to paint.
- The sides are three ways: ba, bc, and ca, with ab in the foreground.
- when the foreground is vertical
- Vertical is two ways
- There are two sides, bc and cb, with a in the foreground.
- The first three ways are vertical, and the sixth way is horizontal.
- The rest can be calculated in any order.
- Official Explanation OK
This page is auto-translated from /nishio/ARC081B using DeepL. If you looks something interesting but the auto-translated English is not good enough to understand it, feel free to let me know at @nishio_en. I’m very happy to spread my thought to non-Japanese readers.