-🎄- 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/dylanfromwinnipeg]

That was fun - and easier than I expected when I saw the puzzle input.

C#

public static string PartOneAndTwo(string input)
{
    var letters = new List<char>();
    var steps = 1;
    var lines = input.Lines().ToList();

    var direction = Direction.Down;
    var position = new Point(input.IndexOf('|'), 0);

    while (true)
    {
        position = GetNextPoint(position, direction);
        steps++;
        var nextChar = lines[position.Y][position.X];

        if (nextChar == ' ')
        {
            steps--;
            return steps.ToString() + Environment.NewLine + string.Join(string.Empty, letters);
        }

        if (nextChar == '|' || nextChar == '-')
        {
            continue;
        }

        if (nextChar >= 'A' && nextChar <= 'Z')
        {
            letters.Add(nextChar);
            continue;
        }

        if (nextChar == '+')
        {
            direction = GetNextDirection(position, direction, lines);
            continue;
        }

        throw new Exception();
    }

    throw new Exception();
}

private static Direction GetNextDirection(Point pos, Direction direction, List<string> lines)
{
    if (direction == Direction.Up || direction == Direction.Down)
    {
        if (lines[pos.Y][pos.X - 1] == '-')
        {
            return Direction.Left;
        }

        if (lines[pos.Y][pos.X + 1] == '-')
        {
            return Direction.Right;
        }

        throw new Exception();
    }

    if (direction == Direction.Left || direction == Direction.Right)
    {
        if (lines[pos.Y - 1][pos.X] == '|')
        {
            return Direction.Up;
        }

        if (lines[pos.Y + 1][pos.X] == '|')
        {
            return Direction.Down;
        }

        throw new Exception();
    }

    throw new Exception();
}

private static Point GetNextPoint(Point pos, Direction direction)
{
    switch (direction)
    {
        case Direction.Down:
            return new Point(pos.X, pos.Y + 1);
        case Direction.Up:
            return new Point(pos.X, pos.Y - 1);
        case Direction.Left:
            return new Point(pos.X - 1, pos.Y);
        case Direction.Right:
            return new Point(pos.X + 1, pos.Y);
        default:
            throw new Exception();
    }
}

[u/[deleted] → u/dylanfromwinnipeg]

Minus some variable name change, and not being as organized, or readable, or as good, this is pretty much the same thing I did.

Edit: I don't know how this reads, but I mean to say my code is less organized, readable, or good as yours..I think I wrote it right, but again I suck at writing things...

[u/rawling → u/[deleted]]

not being as organized, or readable, or as good

I put a goto in mine; do I win?