53 lines
1.4 KiB
Python
53 lines
1.4 KiB
Python
with open('day18-input', 'r') as file:
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data = [l.strip('\n') for l in file]
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import numpy as np
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WIDTH = len(data)
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HEIGHT = len(data[0])
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init_grid = np.zeros((WIDTH+2, HEIGHT+2), dtype=np.int64)
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objects = {'.': 0, '|': 1, '#': 2}
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for y, row in enumerate(data):
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for x, c in enumerate(row):
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init_grid[x+1,y+1] = objects[c]
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grid = init_grid.copy()
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def do_round():
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global grid
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new_grid = np.zeros_like(grid)
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for y in range(1, HEIGHT+1):
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for x in range(1, WIDTH+1):
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ex = grid[x, y]
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square = grid[x-1:x+2, y-1:y+2]
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new = ex
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if ex == 0 and (square == 1).sum() >= 3:
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new = 1
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elif ex == 1 and (square == 2).sum() >= 3:
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new = 2
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elif ex == 2 and not ( (square == 2).sum() >= 2 and (square == 1).sum() > 0 ):
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new = 0
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new_grid[x, y] = new
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grid[:] = new_grid[:]
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for i in range(10):
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do_round()
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print((grid == 2).sum() * (grid == 1).sum()) # Part 1
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past_values = np.zeros(10000, dtype=np.int64)
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grid[:] = init_grid[:]
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for i in range(1000000000):
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past_values[i] = (grid == 2).sum() * (grid == 1).sum()
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m = (past_values == past_values[i-1])
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if m.sum() > 1:
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j = m.argmax()
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if past_values[i] == past_values[j+1]:
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cycle_length = i-j-1
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print(f'Cycle found from {j} to {i-1} minutes! Length {cycle_length} minutes.')
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value = past_values[j + ((1000000000-j)%cycle_length)]
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print(f'After 1000000000 minutes, value will be {value}') # Part 2
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break
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do_round()
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