My Advent of Code solutions in Python.
kevinyap.ca/2019/12/going-fast-in-advent-of-code/
advent-of-code
python
Add solution for 2024/22
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+89
2024/day22.py
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2024/day22.py
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import fileinput
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import itertools
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import functools
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import multiprocessing
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def mix(n, secret):
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return n ^ secret
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def prune(secret):
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return secret % 16777216
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@functools.lru_cache(None)
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def advance(n):
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a = n * 64
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n = mix(n, a)
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n = prune(n)
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a = int(n / 32)
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n = mix(n, a)
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n = prune(n)
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a = n * 2048
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n = mix(n, a)
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n = prune(n)
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return n
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def possible_windows():
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for a, b, c, d in itertools.product(list(range(-9, 10)), repeat=4):
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yield (a, b, c, d)
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def gen_windows(n):
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"""Returns the 2000th secret number and all sliding delta windows."""
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windows = {}
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deltas = []
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last = n
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for i in range(2000 - 1):
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n = advance(n)
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delta = (n % 10) - (last % 10)
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deltas.append(delta)
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last = n
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if len(deltas) >= 4:
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w = tuple(deltas[-4:])
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if w not in windows:
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windows[w] = n % 10
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return advance(n), windows
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def bananas_for_window(window):
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bananas = 0
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for b in BUYERS:
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bananas += ALL_WINDOWS[b].get(window, 0)
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return bananas
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# Read problem input and solve part 1.
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part_1 = 0
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BUYERS = []
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ALL_WINDOWS = {}
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for line in fileinput.input():
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buyer = int(line)
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BUYERS.append(buyer)
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secret_2000, windows = gen_windows(buyer)
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part_1 += secret_2000
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ALL_WINDOWS[buyer] = windows
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# Solve part 2.
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MULTITHREAD = True
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NUM_THREADS = multiprocessing.cpu_count()
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if MULTITHREAD:
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with multiprocessing.Pool(processes=NUM_THREADS) as pool:
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results = pool.map(bananas_for_window, possible_windows())
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else:
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results = []
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for window in possible_windows():
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bananas = bananas_for_window(window)
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results.append(bananas)
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print("Part 1:", part_1)
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print("Part 2:", max(results))