Day 2: Red-Nosed Reports

Megathread guidelines

  • Keep top level comments as only solutions, if you want to say something other than a solution put it in a new post. (replies to comments can be whatever)
  • You can send code in code blocks by using three backticks, the code, and then three backticks or use something such as https://blocks.programming.dev if you prefer sending it through a URL

FAQ

  • @Andy@programming.dev
    4•7 days ago

    Factor

    : get-input ( -- reports )
  "vocab:aoc-2024/02/input.txt" utf8 file-lines
  [ split-words [ string>number ] map ] map ;

: slanted? ( report -- ? )
  { [ [ > ] monotonic? ] [ [ < ] monotonic? ] } || ;

: gradual? ( report -- ? )
  [ - abs 1 3 between? ] monotonic? ;

: safe? ( report -- ? )
  { [ slanted? ] [ gradual? ] } && ;

: part1 ( -- n )
  get-input [ safe? ] count ;

: fuzzy-reports ( report -- reports )
  dup length <iota> [ remove-nth-of ] with map ;

: tolerable? ( report -- ? )
  { [ safe? ] [ fuzzy-reports [ safe? ] any? ] } || ;

: part2 ( -- n )
  get-input [ tolerable? ] count ;