- Thoughts.
- When adjacent squares are of different colors, they are good walls to pass through.
- This relationship is symmetric
- That is, the connected component of an undirected graph
- UnionFind then triangle number - A kind of Frequency→Triangular number.
- Official Explanation
- Missed the “black and white pair.”
- I thought it was two arbitrary points.
- Black x white” instead of triangular numbers
- Missed the “black and white pair.”
This page is auto-translated from /nishio/aising2019C 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.