Day 4: Scratchcards

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  • Andy@programming.dev
    3·
    1 year ago

    Factor on github (with comments):

    USING: io.encodings.utf8 io.files kernel math math.parser
prettyprint ranges sequences sets splitting ;
IN: aoc-2023.day04

: 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  swap '[ _ follow-card ]         
  map-sum .                                         
;

    Lemmy mangles the line in part2 that starts with dup length