Parnic
2a50f6f36c
Following the formula for part 1 was straightforward enough, but finding the pattern for part 2 and deducing the shortcut formula took me a while. That first 0 1 propagate enough that by the time we get halfway through applying the formula, it's all 0s and 1s, so sort of like an addition with a mask on what numbers we're adding.
Advent of Code 2019
My solutions to Advent of Code 2019.