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userturkey13 sieg/heil  1yr ago (text post) 458 thread views #129718

Advent of Code 2022: Day 8

Post solutions here :marseysad: :marseyill:

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You can make things somewhat easier for yourself by using 2d index vectors and

def addv2(v1, v2):
    return v1[0] + v2[0], v1[1] + v2[1]

It didn't get rid of all the bullshit, but of enough of it imo:

def problem8(data, second):
    _data = split_data('''30373
25512
65332
33549
35390''')
    h = len(data)
    w = len(data[0])
    assert all(len(s) == w for s in data)

    vis = set()

    def dix(pos):
        return data[pos[0]][pos[1]]

    def go(pos, dir, cnt):
        tallest = None
        for _ in range(cnt):
            h = dix(pos)
            if not tallest or tallest < h:
                vis.add(pos)
                tallest = h
            pos = addv2(pos, dir)

    def go2(pos, dir):
        myh = dix(pos)
        for i in range(1000):
            pos = addv2(pos, dir)
            if not (0 <= pos[0] < h) or not (0 <= pos[1] < w):
                return i
            if myh <= dix(pos):
                return i + 1
        assert False

    for i in range(h):
        go((i, 0), (0, 1), w)
        go((i, w - 1), (0, -1), w)

    for i in range(w):
        go((0, i), (1, 0), h)
        go((h - 1, i), (-1, 0), h)

    if not second:
        return len(vis)

    scores = []
    for i in range(1, h - 1):
        for j in range(1, w - 1):
            pos = (i, j)
            scores.append(
                go2(pos, (0, 1)) *
                go2(pos, (0, -1)) *
                go2(pos, (1, 0)) *
                go2(pos, (-1, 0)))

    return max(scores)
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>for i in range(1000):

:#marseykneel:

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You can make things somewhat easier for yourself by using 2d index vectors and

this but also by making a complexity monster :gigachad:. I hope the input's dimension won't get too high in the next days

![](/images/1670495109403427.webp)

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>c arrays in c++

:marseybeansick:

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das rite, any problems with dat, white boi?

:#chadblack:

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Yes i have , Use std::array :marseybeandefiant:

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:#chadnocapy::#chadseethecapy::#capyantischizo:

https://yosefk.com/c++fqa/picture.html#fqa-6.15

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Coming from the guy using iostream

:chadcopecapy::chaddilatecapy::chadsneedcapy:

https://yosefk.com/c++fqa/io.html#fqa-15.1

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Yes.

:#chadyes:

the FQA is correct, that doesn't meant that std::istream & co aren't convenient for basic tasks

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true king , let's hope "std::print" will in the future replace "ostream" though.

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you can tell how smart someone is from their solution lol, makes sense you're from motte

an even better solution is just numpy tho:

import numpy as np
p = np.array([[int(b) for b in a] for a in open('/tmp/test').read().split('\n')[:-1]])
ac0 = lambda f, i, j: f(p[i,j], p[:i,j][::-1],p[i+1:,j],p[i,:j][::-1],p[i,j+1:])
acc = lambda f: np.apply_along_axis(lambda ii: ac0(f, ii[0], ii[1]), 0, np.indices(p.shape))
a1 = acc(lambda a,*b: any(all(x < a for x in B) for B in b)).sum()
def r(a,b):
  i = [B >= a for B in b]
  return 1+i.index(True) if True in i else len(b)
a2 = acc(lambda a,*b: np.prod([r(a,B) for B in b])).max()
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Jesse what the frick are you talking about??

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