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58 lines
1.4 KiB
58 lines
1.4 KiB
import itertools
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import typing
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def matrix_spiral(matrix: list[list[typing.Any]]) -> list[typing.Any]:
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return [matrix[y][x] for x, y in matrix_spiral_path(matrix)]
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def matrix_spiral_path(matrix: list[list[int]]) -> list[tuple[int, int]]:
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snek = SpinSnek(matrix)
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while snek.step():
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...
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return snek.path
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COMPASS = (
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(1, 0), # east
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(0, 1), # south
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(-1, 0), # west
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(0, -1), # north
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)
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class SpinSnek:
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def __init__(self, board: list[list[int]], loc: tuple[int, int] = (0, 0)):
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self.max_loc: tuple[int, int] = (len(board[0]) - 1, len(board) - 1)
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self.spinner: itertools.cycle[tuple[int, int]] = itertools.cycle(COMPASS)
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self.direction = next(self.spinner)
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self.path: list[tuple[int, int]] = [loc]
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self.missteps: int = 0
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def step(self) -> bool:
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loc = self.path[-1]
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next_loc: tuple[int, int] = (
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loc[0] + self.direction[0],
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loc[1] + self.direction[1],
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)
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if (
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next_loc[0] > self.max_loc[0]
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or next_loc[1] > self.max_loc[1]
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or next_loc[0] < 0
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or next_loc[1] < 0
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or next_loc in self.path
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):
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self.direction = next(self.spinner)
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if self.missteps > len(COMPASS) - 1:
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return False
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self.missteps += 1
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return self.step()
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self.missteps: int = 0
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self.path.append(next_loc)
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return True
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