|
- def reflect(pos, dirx):
- match '-' if dirx.real else '|', graph.get(pos, ' '):
- case [_, ' ']: return []
- case [_, '.']: return [0]
- case ['-', '-']: return [0]
- case ['-', 'L']: return [1]
- case ['-', '/']: return [-1]
- case ['-', '|']: return [1, -1]
- case ['|', '|']: return [0]
- case ['|', '/']: return [1]
- case ['|', 'L']: return [-1]
- case ['|', '-']: return [1, -1]
- case other: raise RuntimeError(other)
-
-
- def solve(start):
- seen = set()
- state = {start}
- while state:
- seen |= state
- state = {(pp + dd * 1j ** rr, dd * 1j ** rr) for pp, dd in state for rr in reflect(pp, dd)} - seen
- return len({x for x, y in seen} & set(graph))
-
-
- text = open(0).read().replace('\\', 'L')
- graph = {
- complex(x, y): val
- for y, row in enumerate(text.splitlines())
- for x, val in enumerate(row)
- }
- print(solve((0, 1)))
-
- xmin, *_, xmax = sorted(int(p.real) for p in graph)
- ymin, *_, ymax = sorted(int(p.imag) for p in graph)
- starts = []
- starts += [(complex(x, ymin), 1j) for x in range(xmin, xmax + 1)]
- starts += [(complex(x, ymax),-1j) for x in range(xmin, xmax + 1)]
- starts += [(complex(xmin, y), 1 ) for y in range(ymin, ymax + 1)]
- starts += [(complex(xmax, y),-1 ) for y in range(ymin, ymax + 1)]
- print(max(solve(start) for start in starts))
|
