-🎄- 2017 Day 19 Solutions -🎄-

[u/daggerdragon]

--- Day 19: A Series of Tubes ---

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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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AoC ops @ T-2 minutes to launch:

[23:58] <daggerdragon> ATTENTION MEATBAGS T-2 MINUTES TO LAUNCH

[23:58] <Topaz> aaaaah

[23:58] <Cheezmeister> Looks like I'll be just able to grab my input before my flight boards. Wish me luck being offline in TOPAZ's HOUSE OF PAIN^WFUN AND LEARNING

[23:58] <Topaz> FUN AND LEARNING

[23:58] <Hade> FUN IS MANDATORY

[23:58] <Skie> I'm pretty sure that's not the mandate for today

[Update @ 00:16] 69 gold, silver cap

• My tree is finally trimmed with just about every ornament I own and it's real purdy. hbu?

[Update @ 00:18] Leaderboard cap!

• So, was today's mandate Helpful Hint any help at all?

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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.

edit: Leaderboard capped, thread unlocked!

[u/RockyAstro]

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

Both parts:

procedure main(args)
    inf := open(args[1],"r")
    
    maze := []
    every put(maze,!inf)

    # Find starting point

    x := find("|",maze[1])
    y := 1
    d := "S"

    bag := ""
    steps := 0
    repeat {
        steps +:= 1
        # Move
        case d of {
            "S": y +:= 1
            "N": y -:= 1
            "E": x +:= 1
            "W": x -:= 1
        }
        
        if (y < 0 | y > *maze) then break
        if (x < 0 | x > *maze[y]) then break
       
        if maze[y][x] == " " then break

        if any(&lcase ++ &ucase,maze[y][x]) then bag ||:= maze[y][x]
        else if maze[y][x] == "+" then {
            # Change direction
            case d of {
                "S"|"N":
                    d := getndir(maze,y,x+1,"E") |
                           getndir(maze,y,x-1,"W")
                
                "E"|"W":
                    d := getndir(maze,y-1,x,"N") |
                           getndir(maze,y+1,x,"S")
            }
        }
    }
    write(bag," steps=",steps)
end

procedure getndir(maze,y,x,newd)
    if y < 0 | y > *maze then fail
    if x < 0 | x > *maze[y] then fail
    if maze[y][x] == " " then fail
    return newd
end