46 lines
1.2 KiB
Python
46 lines
1.2 KiB
Python
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from typing import Tuple
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def parse_input() -> list[Tuple[str, int, int, int]]:
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def find_position(code: str) -> range:
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search_range = range(0, 2**len(code)-1)
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for char in code:
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spaces = search_range.stop - search_range.start + 1
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if char in ['F', 'L']:
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search_range = range(search_range.start, search_range.stop - spaces//2)
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elif char in ['B', 'R']:
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search_range = range(search_range.start + spaces//2, search_range.stop)
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return search_range
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passes = []
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with open("input.txt") as file:
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for line in file:
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line_ = line.rstrip()
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row = find_position(line_[:7]).start
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col = find_position(line_[7:]).start
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passes.append((line_, row, col, row*8+col))
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return passes
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BOARDING_PASSES = parse_input()
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SORTED_PASSES = sorted(BOARDING_PASSES, key=lambda t: t[3])
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def solve_p1() -> int:
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return SORTED_PASSES[-1][3]
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def solve_p2() -> int:
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for i in range(1, len(SORTED_PASSES)-2):
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prev_ = SORTED_PASSES[i-1][3]
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curr_ = SORTED_PASSES[i][3]
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if prev_+1 != curr_:
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return curr_-1
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return -1
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print(solve_p1())
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print(solve_p2())
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