• Andy
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    edit-2
    11 months ago

    In Factor:

    Here it is on GitHub with comments and imports.

    : line>cards ( line -- winning-nums player-nums )
      ":|" split rest
      [
        [ CHAR: space = ] trim
        split-words harvest [ string>number ] map
      ] map first2
    ;
    
    : points ( winning-nums player-nums -- n )
      intersect length
      dup 0 > [ 1 - 2^ ] when
    ;
    
    : part1 ( -- )
      "vocab:aoc-2023/day04/input.txt" utf8 file-lines
      [ line>cards points ] map-sum .
    ;
    
    : follow-card ( i commons -- n )
      [ 1 ] 2dip
      2dup nth swapd
      over + (a..b]
      [ over follow-card ] map-sum
      nip +
    ;
    
    : part2 ( -- )
      "vocab:aoc-2023/day04/input.txt" utf8 file-lines
      [ line>cards intersect length ] map
      dup length <iota> swap '[ _ follow-card ]
      map-sum .
    ;