advent-of-code/2022/day14_sand.py

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from __future__ import annotations
def main(filename: str, expected_part_1: int = None, expected_part_2: int = None):
print(f"\n+ Running on {filename}")
with open(filename) as f:
data = f.read().strip().split("\n")
data, deepest_wall = parse_data(data)
solution_part_1 = solve_part_1(data, deepest_wall)
print(f"1. Found {solution_part_1}")
if expected_part_1:
assert expected_part_1 == solution_part_1
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solution_part_2 = solve_part_2(data, deepest_wall)
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print(f"2. Found {solution_part_2}")
if expected_part_2:
assert expected_part_2 == solution_part_2
Point = tuple[int, int]
Walls = set(Point)
def generate_wall(start: Point, end: Point) -> Walls:
walls = {start, end}
if start == end:
return {start}
elif start[0] == end[0]:
ys = (start[1], end[1])
for y in range(min(ys) + 1, max(ys)):
walls.add((start[0], y))
elif start[1] == end[1]:
xs = (start[0], end[0])
for x in range(min(xs) + 1, max(xs)):
walls.add((x, start[1]))
return walls
def parse_data(data: list[str]) -> Walls:
walls = set()
deepest_wall = 0
for line in data:
angles = []
for angle in line.split(" -> "):
angles.append(tuple(map(int, angle.split(","))))
for start, end in zip(angles[:-1], angles[1:]):
if start[1] > deepest_wall:
deepest_wall = start[1]
if end[1] > deepest_wall:
deepest_wall = end[1]
walls.update(generate_wall(start, end))
return walls, deepest_wall
def solve_part_1(walls: Walls, deepest_wall: int) -> int:
sand: Walls = set()
while True:
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sand_x, sand_y = compute_final_position(walls, sand, deepest_wall)
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if sand_y >= deepest_wall:
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print_grid(493, 503, 10, walls, sand)
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return len(sand)
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sand.add((sand_x, sand_y))
def compute_final_position(
walls: Walls, sand: Walls, deepest_wall: int, floor_level: int | None = None
) -> Point:
sand_x, sand_y = 500, 0
while sand_y < deepest_wall:
floor: Walls = set()
if floor_level:
floor = {
(sand_x - 1, floor_level),
(sand_x, floor_level),
(sand_x + 1, floor_level),
}
if (sand_x, sand_y + 1) not in walls | sand | floor:
sand_y += 1
elif (sand_x - 1, sand_y + 1) not in walls | sand | floor:
sand_x -= 1
sand_y += 1
elif (sand_x + 1, sand_y + 1) not in walls | sand | floor:
sand_x += 1
sand_y += 1
else:
return sand_x, sand_y
return sand_x, sand_y
def print_grid(
min_x: int,
max_x: int,
max_y: int,
walls: Walls,
sand: Walls,
floor_level: int | None = None,
) -> None:
for y in range(0, max_y + 1):
for x in range(min_x, max_x + 1):
if (x, y) == (500, 0):
print("+", end="")
elif y == floor_level:
print("#", end="")
elif (x, y) in walls:
print("#", end="")
elif (x, y) in sand:
print("o", end="")
else:
print(".", end="")
print()
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def solve_part_2(walls: Walls, deepest_wall: int) -> int:
sand: Walls = set()
sand_x, sand_y = 0, 0
while (sand_x, sand_y) != (500, 0):
sand_x, sand_y = compute_final_position(
walls, sand, deepest_wall + 2, deepest_wall + 2
)
sand.add((sand_x, sand_y))
return len(sand)
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if __name__ == "__main__":
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main("inputs/day14-test1", expected_part_1=24, expected_part_2=93)
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main("inputs/day14", expected_part_1=843, expected_part_2=27625)
# part 2 "only" took 43 minutes 32s on my M1 Pro MacBook Pro.