My Advent of Code solutions in Python.
kevinyap.ca/2019/12/going-fast-in-advent-of-code/
advent-of-code
python
Add 2022/18
+95
+95
2022/day18.py
+95
2022/day18.py
···
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import fileinput
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from collections import deque
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from utils import parse_nums, memoize
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cubes = []
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min_x = 1e9
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max_x = -1e9
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min_y = 1e9
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max_y = -1e9
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min_z = 1e9
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max_z = -1e9
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for line in fileinput.input():
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x, y, z = parse_nums(line)
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cubes.append((x, y, z))
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min_x = min(x, min_x)
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max_x = max(x, max_x)
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min_y = min(y, min_y)
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max_y = max(y, max_y)
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min_z = min(z, min_z)
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max_z = max(z, max_z)
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cubes = set(cubes)
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OFFSETS = [
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(-1, 0, 0),
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(1, 0, 0),
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(0, -1, 0),
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(0, 1, 0),
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(0, 0, -1),
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(0, 0, 1),
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]
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def outside(x, y, z):
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xx = min_x <= x < max_x
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yy = min_y <= y < max_y
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zz = min_z <= z < max_z
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return not (xx and yy and zz)
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KNOWN_INTERNALS = set()
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def is_internal(node):
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global KNOWN_INTERNALS
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seen = set()
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horizon = deque([node])
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while horizon:
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n = horizon.popleft()
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x, y, z = n
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if n in seen:
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continue
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if n in KNOWN_INTERNALS:
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return True
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if outside(*n):
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return False
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seen.add(n)
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for dx, dy, dz in OFFSETS:
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nx = x + dx
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ny = y + dy
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nz = z + dz
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if (nx, ny, nz) in cubes:
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continue
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horizon.append((nx, ny, nz))
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# We are internal, so add everything we've seen to KNOWN_INTERNALS.
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KNOWN_INTERNALS |= seen
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return True
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part_1 = 0
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part_2 = 0
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for x, y, z in cubes:
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for dx, dy, dz in OFFSETS:
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nx, ny, nz = x + dx, y + dy, z + dz
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if (nx, ny, nz) not in cubes:
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part_1 += 1
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if not is_internal((nx, ny, nz)):
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part_2 += 1
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print("Part 1:", part_1)
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print("Part 2:", part_2)