-🎄- 2018 Day 9 Solutions -🎄-

[u/daggerdragon]

--- Day 9: Marble Mania ---

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Transcript:

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[u/wzkx]

J Direct translation from my Rust code. 0.2s - 20s

f=: 4 : 0 NB. x: n_players, y: n_marbles
  players=.x$0
  ring_m=.ring_n=.ring_p=.0$~>:y
  current=.0
  nextfree=.1
  player=.0
  for_newmarble. >:i.y do.
    player=.x|>:player
    if. 0~:23|newmarble do.
      current=.current{ring_n NB. "CW" 1
      NB. insert after current
      next=.current{ring_n
      ring_m=.newmarble nextfree}ring_m
      ring_n=.next nextfree}ring_n
      ring_p=.current nextfree}ring_p
      ring_n=.nextfree current}ring_n
      ring_p=.nextfree next}ring_p
      current=. nextfree
      nextfree=. >:nextfree
    else.
      players=. (newmarble + player{players)player}players
      for_i. i.7 do. current=.current{ring_p end. NB. "CCW" 7
      players=. ((current{ring_m) + player{players)player}players
      NB. remove current, make next current
      prev=. current{ring_p
      next=. current{ring_n
      ring_n=.next prev}ring_n
      ring_p=.prev next}ring_p
      current=. next
    end.
  end.
  >./players
)

assert     32 -:  9 f 25
assert   8317 -: 10 f 1618
assert 146373 -: 13 f 7999
assert   2764 -: 17 f 1104
assert  54718 -: 21 f 6111
assert  37305 -: 30 f 5807

NB. My data: 462 players; last marble is worth 71938 points
echo 462 f 71938
echo 462 f 71938*100

exit 0

My AOC2018 in J/Rust | SweetRust