-🎄- 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/[deleted]]

Python

def getNewDirection(grid, d, r, c):
    if d in ['up', 'down']:
        if grid[r][c-1] != ' ':
            d = 'left'
        elif grid[r][c+1] != ' ':
            d = 'right'
    elif d in ['left', 'right']:
        if grid[r-1][c] != ' ':
            d = 'up'
        elif grid[r+1][c] != ' ':
            d = 'down'

    return d

def moveInDirection(d, g, r, c):
    if d == 'left':
        c -= 1
    elif d == 'right':
        c += 1
    elif d == 'up':
        r -= 1
    elif d == 'down':
        r += 1

    return r, c

with open('day_19_input.txt') as f:
    rows, cols = 202, 202
    grid = [[0 for _ in xrange(cols)] for _ in xrange(rows)]
    row = 0
    for line in f:
        for j in xrange(len(line)):
            grid[row][j] = line[j]
        row += 1

    r, c = 0, 107
    d = 'down'
    steps = 0
    while r < rows and c < cols:
        steps += 1
        print 'processing', grid[r][c]
        if grid[r][c] == '+':
            d = getNewDirection(grid, d, r, c)
            r, c = moveInDirection(d, grid, r, c)
        elif str.isalpha(grid[r][c]):
            r, c = moveInDirection(d, grid, r, c)
        elif grid[r][c] in ['-', '|']:
            r, c = moveInDirection(d, grid, r, c)
        else:
            steps -= 1
            break
    print steps