52 lines
1.5 KiB
Python
52 lines
1.5 KiB
Python
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#!/usr/bin/env python
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# -*- encoding: utf-8; py-indent-offset: 4 -*-
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# Author: Sebastian Mark, Christian Hennevogl
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# CC-BY-SA (https://creativecommons.org/licenses/by-sa/4.0/deed.de)
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# pylint: disable=missing-module-docstring,missing-function-docstring,consider-using-f-string
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def readinput():
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with open("input", "r", encoding="utf-8") as file:
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lines = file.readlines()
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towels = [pattern.strip() for pattern in lines[0].split(",")]
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designs = list(map(str.strip, lines[2:]))
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return towels, designs
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# pylint: disable-next=inconsistent-return-statements
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def check_design(design: str, towels: list, cache=None) -> bool:
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if cache is None:
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cache = {}
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if design in cache: # Check if the result for the current design is already cached.
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return cache[design]
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if not design: # Base case: empty design means it was successfully constructed.
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return True
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for towel in towels:
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if design.startswith(towel): # Check if the design starts with the towel.
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if check_design(design.removeprefix(towel), towels, cache):
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cache[design] = True
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return True
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cache[design] = False # Cache the result as False if no valid combination is found.
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def main():
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towels, designs = readinput()
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# part 1
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sorted_towels = sorted(towels, key=len, reverse=True)
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count = 0
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for design in designs:
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if check_design(design, sorted_towels):
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count += 1
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print("\nPossible designs: %d" % count)
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if __name__ == "__main__":
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main()
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