57 lines
1.5 KiB
Python
57 lines
1.5 KiB
Python
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#!/usr/bin/env python
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import dataclasses
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import sys
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Stack = list[str]
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@dataclasses.dataclass
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class Instruction:
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n: int
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start: int
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end: int
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@classmethod
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def from_input(cls, input: str) -> "Instruction":
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words = input.split()
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return Instruction(int(words[1]), int(words[3]) - 1, int(words[5]) - 1)
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def parse(input: list[str]) -> tuple[list[Stack], list[Instruction]]:
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def parse_stacks(input: list[str]) -> list[Stack]:
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stacks: list[Stack] = [[] for _ in range(1, len(input[-1]), 4)]
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for line in reversed(input[:-1]):
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for stack, i in enumerate(range(1, len(line), 4)):
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c = line[i]
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if c == " ":
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continue
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stacks[stack].append(c)
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return stacks
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def parse_instructions(input: list[str]) -> list[Instruction]:
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return list(map(Instruction.from_input, input))
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empty_line = input.index("")
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return parse_stacks(input[:empty_line]), parse_instructions(input[empty_line + 1 :])
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def solve(input: list[str]) -> str:
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stacks, instructions = parse(input)
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for instr in instructions:
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start, end = stacks[instr.start], stacks[instr.end]
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items = [start.pop() for _ in range(instr.n)]
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items.reverse()
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end.extend(items)
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return "".join(stack[-1] for stack in stacks if stack)
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def main() -> None:
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input = sys.stdin.read().splitlines()
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print(solve(input))
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if __name__ == "__main__":
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main()
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