95 lines
2 KiB
Python
95 lines
2 KiB
Python
from itertools import combinations
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from output import ints
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def solve(data):
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p1 = 0
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p2 = 0
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A = [tuple(ints(pos)) for pos in data.splitlines()]
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S = A[0]
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V = set()
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B = set()
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while True:
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V.add(S)
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y, x = S
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he = [(r, c) for r, c in A if r == y and (r, c) not in V]
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ve = [(r, c) for r, c in A if c == x and (r, c) not in V]
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if not he and not ve:
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E = A[0]
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elif he and ve:
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E = min(min(he), min(ve))
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elif he and not ve:
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E = min(he)
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else:
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E = min(ve)
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y2, x2 = E
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for r in range(min(y, y2), max(y, y2) + 1):
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for c in range(min(x, x2), max(x, x2) + 1):
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B.add((r, c))
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if E == A[0]:
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break
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S = E
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# find out a better start for Flood fill by visualizing
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Y = 1841
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X = 53478
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# or, find a way to floodfill without BFS
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# end
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y, x = Y, X
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Q = [(y, x)]
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V = V | B
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while Q:
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yx = Q.pop()
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if yx in V:
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continue
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V.add(yx)
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y, x = yx
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for dy, dx in D:
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Q.append((dy + y, dx + x))
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for a, b in combinations(A, r=2):
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y1, x1 = a
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y2, x2 = b
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x = abs(x1 - x2) + 1
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y = abs(y1 - y2) + 1
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p1 = max(p1, x * y)
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if (
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len(
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set(
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[
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(min(y1, y2), min(x1, x2)),
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(min(y1, y2), max(x1, x2)),
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(max(y1, y2), min(x1, x2)),
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(max(y1, y2), max(x1, x2)),
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]
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)
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- V
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)
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== 0
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):
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p2 = max(p2, max(p2, x * y))
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return p1, p2
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if __name__ == "__main__":
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inp = """
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7,1
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11,1
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11,7
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9,7
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9,5
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2,5
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2,3
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7,3 """.strip()
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with open("./input/09.txt", "r") as f:
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inp = f.read().strip()
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p1, p2 = solve(inp)
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print(p1)
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print(p2)
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assert p1 == 4749838800
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assert p2 == 1624057680
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