61 lines
1.4 KiB
Python
61 lines
1.4 KiB
Python
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#! /usr/bin/env python3
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from itertools import product
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def main(filename):
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results = {}
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with open(filename) as inp:
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for line in inp:
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boarding_pass = line.rstrip()
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row, col = parse_boarding_pass(boarding_pass)
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seat_id = get_seat_id(row, col)
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results[boarding_pass] = (row, col, seat_id)
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part1(results)
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part2(results)
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def part1(results):
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# part 1
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max_seat_id = max(x[2] for x in results.values())
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print("Max seat ID: ", max_seat_id)
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def part2(results):
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seat_ids = sorted(x[2] for x in results.values())
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missing_seat_ids = set(range(max(seat_ids))) - set(seat_ids)
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print(missing_seat_ids)
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def parse_boarding_pass(boarding_pass):
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row = _parse(boarding_pass[:7], "F", "B", 128)
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col = _parse(boarding_pass[7:], "L", "R", 7)
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return row, col
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def _parse(inp, lower_option, upper_option, number):
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rows = slice(0, number - 1)
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for l in inp:
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if l == lower_option:
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rows = lower_half(rows)
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else:
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rows = upper_half(rows)
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return rows.start
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def lower_half(sl: slice):
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length = sl.stop - sl.start
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return slice(sl.start, sl.start + length // 2)
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def upper_half(sl: slice):
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length = sl.stop - sl.start
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return slice(1 + sl.start + length // 2, sl.stop)
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def get_seat_id(row, col):
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return 8 * row + col
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if __name__ == "__main__":
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main('input.txt')
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