2023 day 22.
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85fff24cc1
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82fab771ab
@ -1,13 +1,111 @@
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import itertools
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import logging
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import os
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import string
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import sys
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import sys
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from collections import defaultdict
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from collections import defaultdict
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from dataclasses import dataclass
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VERBOSE = os.getenv("AOC_VERBOSE") == "True"
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logging.basicConfig(level=logging.INFO if VERBOSE else logging.WARNING)
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lines = sys.stdin.read().splitlines()
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lines = sys.stdin.read().splitlines()
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def _name(i: int) -> str:
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if len(lines) < 26:
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return string.ascii_uppercase[i]
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return f"B{i:04d}"
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def build_supports(
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bricks: list[tuple[tuple[int, int, int], tuple[int, int, int]]]
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) -> tuple[dict[int, set[int]], dict[int, set[int]]]:
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# 1. compute locations where a brick of sand will land after falling by processing
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# them in sorted order of bottom z location
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levels: dict[tuple[int, int, int], int] = defaultdict(lambda: -1)
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for i_brick, ((sx, sy, sz), (ex, ey, ez)) in enumerate(bricks):
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assert sx <= ex and sy <= ey and sz <= ez
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xs, ys = range(sx, ex + 1), range(sy, ey + 1)
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for z in range(sz - 1, 0, -1):
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if any(levels[x, y, z] >= 0 for x, y in itertools.product(xs, ys)):
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break
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sz, ez = sz - 1, ez - 1
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bricks[i_brick] = ((sx, sy, sz), (ex, ey, ez))
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zs = range(sz, ez + 1)
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for x, y, z in itertools.product(xs, ys, zs):
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levels[x, y, z] = i_brick
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# 2. compute the bricks that supports any brick
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supported_by: dict[int, set[int]] = {}
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supports: dict[int, set[int]] = {i_brick: set() for i_brick in range(len(bricks))}
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for i_brick, ((sx, sy, sz), (ex, ey, ez)) in enumerate(bricks):
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name = _name(i_brick)
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supported_by[i_brick] = {
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v
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for x, y in itertools.product(range(sx, ex + 1), range(sy, ey + 1))
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if (v := levels[x, y, sz - 1]) != -1
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}
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logging.info(
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f"{name} supported by {', '.join(map(_name, supported_by[i_brick]))}"
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)
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for support in supported_by[i_brick]:
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supports[support].add(i_brick)
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return supported_by, supports
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bricks: list[tuple[tuple[int, int, int], tuple[int, int, int]]] = []
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for line in lines:
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bricks.append(
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(
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tuple(int(c) for c in line.split("~")[0].split(",")), # type: ignore
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tuple(int(c) for c in line.split("~")[1].split(",")), # type: ignore
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)
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)
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# sort bricks by bottom z position to compute supports
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bricks = sorted(bricks, key=lambda b: b[0][-1])
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supported_by, supports = build_supports(bricks)
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# part 1
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# part 1
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answer_1 = ...
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answer_1 = len(bricks) - sum(
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any(len(supported_by[supported]) == 1 for supported in supports_to)
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for supports_to in supports.values()
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)
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print(f"answer 1 is {answer_1}")
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print(f"answer 1 is {answer_1}")
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# part 2
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# part 2
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answer_2 = ...
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falling_in_chain: dict[int, set[int]] = {}
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for i_brick in range(len(bricks)):
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to_disintegrate: set[int] = {
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supported
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for supported in supports[i_brick]
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if len(supported_by[supported]) == 1
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}
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supported_by_copy = dict(supported_by)
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falling_in_chain[i_brick] = set()
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while to_disintegrate:
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falling_in_chain[i_brick].update(to_disintegrate)
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to_disintegrate_v: set[int] = set()
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for d_brick in to_disintegrate:
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for supported in supports[d_brick]:
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supported_by_copy[supported] = supported_by_copy[supported] - {d_brick}
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if not supported_by_copy[supported]:
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to_disintegrate_v.add(supported)
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to_disintegrate = to_disintegrate_v
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answer_2 = sum(len(falling) for falling in falling_in_chain.values())
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print(f"answer 2 is {answer_2}")
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print(f"answer 2 is {answer_2}")
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File diff suppressed because it is too large
Load Diff
@ -0,0 +1,7 @@
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1,0,1~1,2,1
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0,0,2~2,0,2
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0,2,3~2,2,3
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0,0,4~0,2,4
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2,0,5~2,2,5
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0,1,6~2,1,6
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1,1,8~1,1,9
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