63 lines
2.0 KiB
Python
63 lines
2.0 KiB
Python
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BLACK = "B"
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WHITE = "W"
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NONE = ""
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STONES = [BLACK, WHITE]
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DIRECTIONS = [(0, 1), (0, -1), (1, 0), (-1, 0)]
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class Board:
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def __init__(self, board):
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self.board = board.splitlines()
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self.width = len(self.board[0])
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self.height = len(self.board)
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def valid(self, x, y):
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return x >= 0 and x < self.width and y >= 0 and y < self.height
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def walk(self, x, y,
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visited_territory=[],
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visited_coords=[],
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visited_stones=[]):
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if not (x, y) in visited_coords and self.valid(x, y):
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s = self.board[y][x]
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if s in STONES:
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if s not in visited_stones:
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return (visited_territory, visited_stones + [s])
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else: # s is empty
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for d in DIRECTIONS:
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visited = self.walk(x + d[0], y + d[1],
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visited_territory + [(x, y)],
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visited_coords + [(x, y)],
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visited_stones)
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visited_territory = visited[0]
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visited_stones = visited[1]
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return (visited_territory, visited_stones)
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def territoryFor(self, coord):
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assert len(coord) == 2
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x, y = coord[0], coord[1]
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if not self.valid(x, y) or self.board[y][x] in STONES:
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return (NONE, set())
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visited_territory, visited_stones = self.walk(x, y)
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result = set(visited_territory)
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if len(visited_stones) == 1:
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return (visited_stones[0], result)
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return (NONE, result)
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def territories(self):
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owners = STONES + [NONE]
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result = dict([(owner, set()) for owner in owners])
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visited = set()
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for y in range(self.height):
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for x in range(self.width):
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if not (x, y) in visited:
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owner, owned_territories = self.territoryFor((x, y))
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result[owner].update(owned_territories)
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visited.update(owned_territories)
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return result
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