40 lines
961 B
Python
40 lines
961 B
Python
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from typing import Callable
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from .board import Board
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def solve(
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state: Board,
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is_solved: Callable[[Board], bool],
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*,
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history: list[tuple[int, Board]] | None = None,
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) -> list[tuple[int, Board]] | None:
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if history is None:
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# create starting state
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history = [(-1, state)]
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if is_solved(state):
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return history
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for button in state.buttons:
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# try to click all buttons
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next = state.click(button)
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if next is not None:
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# click successful
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binary_history = (
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state.binary_repr
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for _, state in history
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)
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if next.binary_repr not in binary_history:
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# "next" is a new state
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solution = solve(
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next, is_solved,
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history=[*history, (button, next)]
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)
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if solution is not None:
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return solution
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