Wild

[alper]

Totally wild that this could be done in a fold. Kudos!

AdventOfCode2020/src/bin/15.rs

Line 8 in 1157ff5

(7..target).fold(4, |last, i| i - seen.insert(last, i).unwrap_or(i))

[AxlLind]

Thanks, I appreciate it! This implementation definitely wasn't my initial one but the more I looked at it the more it simplified into a single fold at the end 😅 The fact that HashMap::insert() returns the previous value is really what made it so clean.