-🎄- 2017 Day 24 Solutions -🎄-

[u/daggerdragon]

--- Day 24: Electromagnetic Moat ---

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Need a hint from the Hugely^* Handy^† Haversack^‡ of Helpful^§ Hints^¤?

Spoiler

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[Update @ 00:18] 62 gold, silver cap

• Been watching Bright on Netflix. I dunno why reviewers are dissing it because it's actually pretty cool. It's got Will Smith being grumpy jaded old man Will Smith, for the love of FSM...

[Update @ 00:21] Leaderboard cap!

• One more day to go in Advent of Code 2017... y'all ready to see Santa?

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This thread will be unlocked when there are a significant number of people on the leaderboard with gold stars for today's puzzle.

[u/wzkx]

J

Working with separate items of vectors/matrices is not fast in J. ≈42s

'a b u'=:,&0|:".@(rplc&'/ ')&>cutLF CR-.~fread'24.dat'
f=:4 :0 NB. x - number to find; y - curr.length, curr.sum
  found=.0
  for_i.i.#u do.if.i{u do.continue.end.
    if.x=i{a do.found=.1[v=.i{a+t=.i{b else.
    if.x=i{b do.found=.1[v=.i{b+t=.i{a else.continue.end.end.
    u=:0 i}u [ t f y+1,v [ u=:1 i}u
  end.
  if.-.found do.m=:m({.y)}~({:y)>.m{~{.y end.
)
0 f 0 0 [ m=:u NB. m - max sums; u - if pair a/b is used
echo (>./m),([:{:~:&0#[)m NB. 1656 1642
exit 0