78 lines
1.8 KiB
Python
Executable file
78 lines
1.8 KiB
Python
Executable file
#!/usr/bin/env python
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import re
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import sys
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from collections import defaultdict
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from copy import deepcopy
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from dataclasses import dataclass
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from typing import Dict, List, Set, Tuple
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@dataclass(eq=True, frozen=True) # Hashable
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class ColorInfo:
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num: int
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color: str
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Graph = Dict[str, Set[ColorInfo]]
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def extract_info(line: str) -> Tuple[str, Set[ColorInfo]]:
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color_pattern = re.compile("(.*) contain ")
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match = color_pattern.search(line)
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assert match is not None
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color = match.group(1).replace("bags", "bag")
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line = line[match.end() : -1] # Remove period at end of line
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if line == "no other bags":
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return color, set()
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colors: Set[ColorInfo] = set()
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pattern = re.compile("([0-9]+) (.*)")
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for col in line.split(", "):
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match = pattern.search(col)
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assert match is not None
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colors |= {
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ColorInfo(int(match.group(1)), match.group(2).replace("bags", "bag"))
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}
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return color, colors
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def to_graph(raw: List[str]) -> Graph:
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return {color: inside for color, inside in map(extract_info, raw)}
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def reverse(graph: Graph) -> Graph:
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reverse: Graph = defaultdict(set)
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for color, contained in graph.items():
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for col in contained:
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reverse[col.color] |= {ColorInfo(-1, color)}
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return reverse
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def containing(graph: Graph, col: str) -> Set[ColorInfo]:
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res = deepcopy(graph[col])
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for contains in graph[col]:
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res |= containing(graph, contains.color)
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return res
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def solve(raw: List[str]) -> int:
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graph = to_graph(raw)
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reverse_graph = reverse(graph)
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return len(containing(reverse_graph, "shiny gold bag"))
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def main() -> None:
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input = [line.strip() for line in sys.stdin.readlines()]
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print(solve(input))
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if __name__ == "__main__":
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main()
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