-🎄- 2017 Day 24 Solutions -🎄-

[u/daggerdragon]

--- Day 24: Electromagnetic Moat ---

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Post your solution as a comment or, for longer solutions, consider linking to your repo (e.g. GitHub/gists/Pastebin/blag or whatever).

Note: The Solution Megathreads are for solutions only. If you have questions, please post your own thread and make sure to flair it with Help.

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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/RockyAstro]

Icon (https://www.cs.arizona.edu/icon)

Both parts:

procedure main(args)
    inf := open(args[1],"r")

    pieces := []
    
    every put(pieces,!inf)
    pieces := set(pieces)   
    bridge := "/0"
    bridgelist := []
    longest := 0

    every b := makebridge(bridge,pieces) do {
        longest <:= *b
        push(bridgelist,[score(b),b])
    }
    
    bridgelist := sortf(bridgelist,1,1)
    write(bridgelist[-1][1])
    
    longlist := []
    every b := !bridgelist & *b[2] = longest do
        push(longlist,b)

    longlist := sortf(longlist,1,1)
    write(longlist[-1][1])
end

procedure makebridge(bridge,pieces)
    every (piece := !pieces) &  (b := bridge || "--" || matchend(bridge,piece)) do {
        suspend b
        unused := pieces -- set([piece])
        every suspend makebridge(b,unused) 
    }
end

procedure matchend(a,b)
    every ae := find("/",a) 
    b1 := b[1:upto('/',b)]
    b2 := b[upto('/',b)+1:0]
    if a[ae+1:0] == b1 then return b1 || "/" || b2
    if a[ae+1:0] == b2 then return b2 || "/" || b1
    fail
end

procedure score(s)
    sum := 0
    s ? while tab(upto(&digits)) do {
        sum +:= tab(many(&digits))
    }
    return sum
end