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Faster day 24.

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Mikaël Capelle 2022-12-24 22:59:40 +01:00
parent f2cc3e4d16
commit 0508d95e33
1 changed files with 5 additions and 9 deletions
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14
2022/day24.py
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@ -17,7 +17,6 @@ winds = {
n_rows, n_cols = len(lines) - 2, len(lines[0]) - 2
CYCLE = math.lcm(n_rows, n_cols)
# for each row, set of forward winds
east_winds = [{j for j in range(n_cols) if (i, j, ">") in winds} for i in range(n_rows)]
west_winds = [{j for j in range(n_cols) if (i, j, "<") in winds} for i in range(n_rows)]
north_winds = [
@ -32,14 +31,13 @@ def run(start: tuple[int, int], start_cycle: int, end: tuple[int, int]):
def heuristic(y: int, x: int) -> int:
return abs(end[0] - y) + abs(end[1] - x)
# (distance + heuristic, distance, start_pos)
# (distance + heuristic, distance, (start_pos, cycle))
queue = [(heuristic(start[0], start[1]), 0, ((start[0], start[1]), start_cycle))]
visited: set[tuple[tuple[int, int], int]] = set()
distances: dict[tuple[int, int], dict[int, int]] = defaultdict(lambda: {})
while queue:
_, distance, ((y, x), cycle) = heapq.heappop(queue)
# print(y, x, distance, cycle)
if ((y, x), cycle) in visited:
continue
@ -68,17 +66,15 @@ def run(start: tuple[int, int], start_cycle: int, end: tuple[int, int]):
continue
if (ty, tx) != start:
if any(ty == (vy + n_cycle) % n_rows for vy in south_winds[tx]):
if (ty - n_cycle) % n_rows in south_winds[tx]:
continue
if any(ty == (vy - n_cycle) % n_rows for vy in north_winds[tx]):
if (ty + n_cycle) % n_rows in north_winds[tx]:
continue
if any(tx == (vx - n_cycle) % n_cols for vx in west_winds[ty]):
if (tx + n_cycle) % n_cols in west_winds[ty]:
continue
if any(tx == (vx + n_cycle) % n_cols for vx in east_winds[ty]):
if (tx - n_cycle) % n_cols in east_winds[ty]:
continue
# print(f"{y} {x} [{cycle}] -> {ty} {tx}")
heapq.heappush(
queue,
((heuristic(ty, tx) + distance + 1, distance + 1, ((ty, tx), n_cycle))),