2023/day14.py

import sys
from pprint import pprint
from copy import deepcopy


def shift(map, dx, dy):
    for y in range(max(0, -dy), len(map) - max(0, dy)):
        for x in range(max(0, -dx), len(map) - max(0, dx)):
            (x1, y1) = (x, y)
            while True:
                (x2, y2) = (x1 + dx, y1 + dy)
                if 0 <= y2 < len(map) and 0 <= x2 < len(map[y2]) and map[y2][x2] == ".":
                    (x1, y1) = (x2, y2)
                else:
                    break

            if (x1, y1) != (x, y):
                map[y1][x1] = "O"
                map[y][x] = "."


def weigh(map):
    return sum((len(map) - y) * row.count("O") for (y, row) in enumerate(map))


# @profile
def main():
    CYCLES = 1_000_000_000

    with open(sys.argv[1]) as f:
        map = [[c for c in l] for l in f.read().strip().splitlines()]

    part1 = 0
    pprint(map)
    shift(map, 0, -1)
    pprint(map)
    part1 = weigh(map)
    shift(map, -1, 0)
    pprint(map)
    shift(map, 0, 1)
    pprint(map)
    shift(map, 1, 0)
    pprint(map)

    for i in range(1, 100):
        shift(map, 0, -1)
        shift(map, -1, 0)
        shift(map, 0, 1)
        shift(map, 1, 0)

    seen = {}
    history = []
    (i, j) = (0, 0)
    for i in range(100, CYCLES):
        shift(map, 0, -1)
        shift(map, -1, 0)
        shift(map, 0, 1)
        shift(map, 1, 0)

        s = str(map)
        history.append(weigh(map))
        if s in seen:
            j = seen[s]
            break
        seen[s] = i

    offset = (CYCLES - j) % (i - j) - 1
    part2 = history[offset]

    print(part1, part2)


main()