Day 12: Christmas Tree Farm

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[–] 4 points 7 months ago* (last edited 7 months ago) (2 children)

Python

You got me good, Eric.

hintThink of the simplest check you can make for a region.

click to view code

# This does not work for the sample :D

def solve(data: str):
    # split input
    blocks = data.split("\n\n")
    shape_blocks = blocks[:-1]
    region_block = blocks[-1]

    # for every shape, get the number of occupied cells
    shape_area = []
    for shape_block in shape_blocks:
        shape_area.append(shape_block.count('#'))

    fit_regions = 0

    # for every region, check if the area is sufficient to fit all shapes
    for region_data in region_block.splitlines():
        size_data, shape_data = region_data.split(': ')

        # get region size
        m, n = [int(dim) for dim in size_data.split('x')]

        # get area needed to fit all shapes, without considering arrangement
        area_needed = 0
        for id, freq in enumerate(map(int, shape_data.split(' '))):
            area_needed += shape_area[id] * freq
        
        # if the region area is sufficient, count it as a fit (!!!)
        if m * n > area_needed:
            fit_regions += 1
    
    return fit_regions

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  • [–] 4 points 7 months ago* (last edited 7 months ago) (1 child)

    Mild spoilers ahead, but you're reading the solutions thread.

    I was just doing some preliminary checking of the data on my phone with Nushell (to see how much my ageing laptop would suffer) when I discovered there weren't any non trivial cases.

    Normally I get the test data working before trying the input data, this is definitely teaching me the value of investigating the data before heading down into the code mines.

    Unfortunately I can't get the second star yet because I missed a few days.

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  • [–] 2 points 7 months ago* (1 child)

    I actually did a lot of optimizations before I had to give up and search what I was missing. I did have a look at my input data, but still wouldn't make the connection because in my mind, any solution had to work for the sample too.

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  • [–] [S] 2 points 7 months ago (1 child)

    spoilerI had an feeling it would be trivial, but didnt think it would be that trivial. I got the answer without even parsing the shapes, just called them all 9.

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