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- #!/usr/bin/env python3
- import sys
- def energize(grid, x, y, dx, dy, visited=None):
- visited = {} if visited is None else visited
- while 0 <= x < len(grid[0]) and 0 <= y < len(grid):
- directions = visited.setdefault((x, y), [])
- if (dx, dy) in directions:
- break
- directions.append((dx, dy))
- cell = grid[y][x]
- if cell in '/\\':
- dx, dy = (dy, -dx) if (dx if cell == '/' else dy) else (-dy, dx)
- elif cell == '-' and dy:
- energize(grid, x + 1, y, 1, 0, visited)
- dx, dy = -1, 0
- elif cell == '|' and dx:
- energize(grid, x, y + 1, 0, 1, visited)
- dx, dy = 0, -1
- x += dx
- y += dy
- return len(visited)
- def energies(grid):
- w = len(grid[0])
- h = len(grid)
- for x in range(w):
- yield energize(grid, x, 0, 0, 1)
- yield energize(grid, x, h - 1, 0, -1)
- for y in range(h):
- yield energize(grid, 0, y, 1, 0)
- yield energize(grid, w - 1, y, -1, 0)
- grid = [line.rstrip() for line in sys.stdin]
- print(energize(grid, 0, 0, 1, 0))
- print(max(energies(grid)))
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