parent
d03225edce
commit
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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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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(
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[
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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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)
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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 > 3:
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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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@ -0,0 +1,46 @@
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import pytest
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import spiral_matrix
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@pytest.mark.parametrize(
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("matrix", "expected"),
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[
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(
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[
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["a", "b", "c"],
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["d", "e", "f"],
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["g", "h", "i"],
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],
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["a", "b", "c", "f", "i", "h", "g", "d", "e"],
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),
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(
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[
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[1, 2, 3, 4],
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[5, 6, 7, 8],
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[9, 10, 11, 12],
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],
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[1, 2, 3, 4, 8, 12, 11, 10, 9, 5, 6, 7],
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),
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(
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[
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[1, 2, 3, 4, 5, 6, 7, 8, 9],
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[1, 2, 3, 4, 5, 6, 7, 8, 9],
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[1, 2, 3, 4, 5, 6, 7, 8, 9],
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[1, 2, 3, 4, 5, 6, 7, 8, 9],
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[1, 2, 3, 4, 5, 6, 7, 8, 9],
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],
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[]
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+ [1, 2, 3, 4, 5, 6, 7, 8, 9] # right
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+ [9, 9, 9] # down
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+ [9, 8, 7, 6, 5, 4, 3, 2, 1] # left
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+ [1, 1] # up
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+ [1, 2, 3, 4, 5, 6, 7, 8] # right
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+ [8] # down
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+ [8, 7, 6, 5, 4, 3, 2] # left
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+ [2, 3, 4, 5, 6, 7], # right
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),
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],
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)
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def test_matrix_spiral(matrix, expected):
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assert spiral_matrix.matrix_spiral(matrix) == expected
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