43 lines
1.3 KiB
Python
43 lines
1.3 KiB
Python
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def main():
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with open("day6.txt", "rt") as input_file:
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lines = input_file.readlines()
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entries = [tuple(line.rstrip().split(")")) for line in lines]
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orbit_map = build_map(entries)
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# Part 1
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num_orbits = sum(count_orbits(orbit_map, s) for s in orbit_map.keys())
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print("Num orbits:", num_orbits)
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# Part 2
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you_cursor, san_cursor = orbit_map["YOU"], orbit_map["SAN"]
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you_way, san_way = [], []
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jumps = 0
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while you_cursor is not None or san_cursor is not None:
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you_cursor = orbit_map.get(you_cursor)
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san_cursor = orbit_map.get(san_cursor)
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you_way.append(you_cursor)
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san_way.append(san_cursor)
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if you_cursor in san_way:
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jumps = san_way.index(you_cursor) + len(you_way)
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break
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if san_cursor in you_way:
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jumps = you_way.index(san_cursor) + len(san_way)
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break
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print("Required jumps:", jumps + 1)
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def build_map(entries):
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orbit_map = {}
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for center, satellite in entries:
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orbit_map[satellite] = center
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return orbit_map
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def count_orbits(orbit_map, satellite):
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if satellite in orbit_map:
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return 1 + count_orbits(orbit_map, orbit_map[satellite])
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else:
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return 0
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if __name__ == "__main__":
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main()
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