Advent of Code 2024 Day 22

from pathlib import Path
from typing import Sequence
from collections import deque, Counter
from itertools import islice


def parse(input: str) -> list[int]:
    return [int(n) for n in input.splitlines()]


def step(secret: int) -> int:
    secret = (secret ^ (secret * 64)) % 16777216
    secret = (secret ^ secret // 32) % 16777216
    secret = (secret ^ (secret * 2048)) % 16777216
    return secret


def nth_secret(secret: int, n: int) -> int:
    for _ in range(n):
        secret = step(secret)
    return secret


def part1(data: list[int], steps: int) -> int:
    return sum(nth_secret(secret, steps) for secret in data)


TEST = parse(Path("input/day22-test.txt").read_text())
assert part1(TEST, 2000) == 37327623
INPUT = parse(Path("input/day22.txt").read_text())
part1_total = part1(INPUT, 2000)
print(f"{part1_total=:,}")  # 14,726,157,693


def sliding_window(iterable, n):
    "Collect data into overlapping fixed-length chunks or blocks."
    # sliding_window('ABCDEFG', 4) → ABCD BCDE CDEF DEFG
    iterator = iter(iterable)
    window = deque(islice(iterator, n - 1), maxlen=n)
    for x in iterator:
        window.append(x)
        yield tuple(window)


def prices(secret: int, steps: int = 2000) -> Sequence[tuple[int, int]]:
    last = secret % 10
    for i in range(steps):
        secret = step(secret)
        s = secret % 10
        yield s, s - last
        last = s


def sequences(secret: int, steps: int = 2000) -> Sequence[tuple[str, int]]:
    for w in sliding_window(prices(secret, steps), 4):
        key = f"{w[0][1]}{w[1][1]}{w[2][1]}{w[3][1]}"
        value = w[3][0]
        yield key, value


def sell_dict(secret: int, steps: int = 2000) -> dict[str, int]:
    seq = list(sequences(secret, steps))
    return dict(reversed(seq))


def part2(data: list[str]) -> int:
    bananas = Counter()
    for secret in data:
        d = sell_dict(secret)
        bananas.update(d)

    # print(bananas.most_common(1))
    return bananas.most_common(1)[0][1]


assert part2([1, 2, 3, 2024]) == 23
part2_total = part2(INPUT)
print(f"{part2_total=:,}")  # 1,614