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- @lambda fn: lambda brick: set(fn(brick))
- def dimension(brick):
- (x1, x2), (y1, y2), (z1, z2) = map(sorted, zip(*brick))
- for z in range(z1, z2 + 1):
- for y in range(y1, y2 + 1):
- for x in range(x1, x2 + 1):
- yield x, y, z
-
-
- def tetris(bricks):
- floor = {(x, y, 0) for x in range(100) for y in range(100)}
- seen = floor
- for brick in map(dimension, bricks):
- while not seen & brick:
- brick = {(x, y, z - 1) for x, y, z in brick}
- resting_place = {(x, y, z + 1) for x, y, z in brick}
- seen |= resting_place
- yield resting_place
-
-
- def topple(i, depends_on, holds_up):
- gone = set()
- state = {i}
- while state:
- gone |= state
- state = {above
- for below in state
- for above in depends_on.get(below, [])
- if holds_up[above] <= gone
- }
- return gone - {i}
-
-
- text = open(0).read()
- bricks = [[[int(n) for n in sub.split(',')] for sub in line.split('~')] for line in text.splitlines()]
- bricks.sort(key=lambda brick: min(z for x, y, z in brick))
- bricks = list(tetris(bricks))
-
- known = {i for i, _ in enumerate(bricks)}
- holds_up, depends_on = {}, {}
- for j, brick in enumerate(bricks):
- j_brick_1_down = {(x, y, z - 1) for x, y, z in brick}
- holds_up[j] = {i for i, i_brick in enumerate(bricks) if i != j and j_brick_1_down & i_brick}
- for i in holds_up[j]:
- depends_on.setdefault(i, set()).add(j)
-
- needed = {v for k, vs in holds_up.items() if len(vs) == 1 for v in vs}
- print(len(known - needed))
- print(sum(len(topple(i, depends_on, holds_up)) for i in needed))
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