My Advent of Code solutions in Python.
kevinyap.ca/2019/12/going-fast-in-advent-of-code/
advent-of-code
python
Add solution for 2023/12
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+57
2023/day12.py
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2023/day12.py
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import fileinput
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from utils import memoize
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@memoize
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def ways(spring, groups):
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# Base cases
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if len(spring) == 0:
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if not groups:
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return 1
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else:
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return 0
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# trust_the_natural_recursion.jpg
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if spring[0] == '#':
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if not groups:
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return 0
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if any(c == '.' for c in spring[:groups[0]]):
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return 0
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if len(spring) == groups[0]:
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if len(groups) == 1:
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return 1
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else:
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return 0
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if len(spring) < groups[0]:
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return 0
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# If the character after this "group" is a `#`, we have a mismatch.
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if spring[groups[0]] == '#':
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return 0
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return ways(spring[groups[0]+1:], groups[1:])
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elif spring[0] == '.':
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return ways(spring[1:], groups)
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elif spring[0] == '?':
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return ways('#' + spring[1:], groups) + ways('.' + spring[1:], groups)
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part_1 = 0
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part_2 = 0
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for line in fileinput.input():
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spring, groups = line.strip().split()
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groups = tuple(int(n) for n in groups.split(','))
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part_1 += ways(spring, groups)
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part_2 += ways('?'.join(spring for _ in range(5)), groups * 5)
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print("Part 1:", part_1)
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print("Part 2:", part_2)
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