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80 lines
1.8 KiB
80 lines
1.8 KiB
3 years ago
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import numpy as np
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with open("input") as file:
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rows = file.read().splitlines()
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numbers = np.array([[int(num) for num in row] for row in rows])
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def shift2D(arr, amount, vert=False, d=0):
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shifted = np.empty_like(arr)
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if vert:
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if amount > 0:
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shifted[:amount] = d
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shifted[amount:] = arr[:-amount]
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else:
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shifted[amount:] = d
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shifted[:amount] = arr[-amount:]
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else:
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if amount > 0:
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shifted[:, :amount] = d
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shifted[:, amount:] = arr[:, :-amount]
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else:
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shifted[:, amount:] = d
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shifted[:, :amount] = arr[:, -amount:]
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return shifted
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def getLowPointsMask():
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m = np.max(numbers) + 1
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shR = shift2D(numbers, 1, d=m)
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shL = shift2D(numbers, -1, d=m)
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shU = shift2D(numbers, -1, True, d=m)
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shD = shift2D(numbers, 1, True, d=m)
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mask = (numbers < shR) & (numbers < shL) & (numbers < shU) & (numbers < shD)
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return mask
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def solve1():
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lowPoints = numbers[getLowPointsMask()]
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return np.sum(lowPoints + 1)
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def solve2():
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m = -1
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shR = shift2D(numbers, 1, d=m)
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shL = shift2D(numbers, -1, d=m)
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shU = shift2D(numbers, -1, True, d=m)
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shD = shift2D(numbers, 1, True, d=m)
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leftGreater = numbers < shR
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rightGreater = numbers < shL
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upGreater = numbers < shD
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downGreater = numbers < shU
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def search(fromX, fromY):
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if (fromX, fromY) in visited or numbers[fromY][fromX] == 9:
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return
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visited.add((fromX, fromY))
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if leftGreater[fromY, fromX]:
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search(fromX - 1, fromY)
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if rightGreater[fromY, fromX]:
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search(fromX + 1, fromY)
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if downGreater[fromY, fromX]:
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search(fromX, fromY + 1)
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if upGreater[fromY, fromX]:
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search(fromX, fromY - 1)
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sizes = [0, 0, 0]
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for y, x in np.transpose(np.where(getLowPointsMask())):
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visited = set()
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search(x, y)
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n = len(visited)
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if n > min(sizes):
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sizes.remove(min(sizes))
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sizes.append(n)
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return sizes[0] * sizes[1] * sizes[2]
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print(solve1())
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print(solve2())
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