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from collections import deque
from enum import Enum, auto
from sys import stdin
class Dir(Enum):
NORTH = auto()
EAST = auto()
SOUTH = auto()
WEST = auto()
def step(direction: Dir, pos: tuple[int, int]) -> tuple[int, int]:
match direction:
case Dir.NORTH:
return pos[0], pos[1] - 1
case Dir.EAST:
return pos[0] + 1, pos[1]
case Dir.SOUTH:
return pos[0], pos[1] + 1
case Dir.WEST:
return pos[0] - 1, pos[1]
inp = [line.rstrip("\n") for line in stdin]
def solve(inp: list[str], start: tuple[Dir, tuple[int, int]]) -> int:
beams: deque[tuple[Dir, tuple[int, int]]] = deque((start,))
old_beams: set[tuple[Dir, tuple[int, int]]] = set()
covered: set[tuple[int, int]] = set()
def add(direction: Dir, pos: tuple[int, int]):
t = (direction, step(direction, pos))
if t in old_beams:
return
old_beams.add(t)
beams.append(t)
while beams:
direction, pos = beams.popleft()
x, y = pos
if x < 0 or x >= len(inp[0]) or y < 0 or y >= len(inp):
continue
covered.add(pos)
c = inp[y][x]
if (
c == "."
or (c == "-" and direction in {Dir.EAST, Dir.WEST})
or (c == "|" and direction in {Dir.NORTH, Dir.SOUTH})
):
add(direction, pos)
elif c == "|":
add(Dir.NORTH, pos)
add(Dir.SOUTH, pos)
elif c == "-":
add(Dir.EAST, pos)
add(Dir.WEST, pos)
else:
mapping: dict[tuple[str, Dir], Dir] = {
("/", Dir.NORTH): Dir.EAST,
("/", Dir.EAST): Dir.NORTH,
("/", Dir.SOUTH): Dir.WEST,
("/", Dir.WEST): Dir.SOUTH,
("\\", Dir.NORTH): Dir.WEST,
("\\", Dir.EAST): Dir.SOUTH,
("\\", Dir.SOUTH): Dir.EAST,
("\\", Dir.WEST): Dir.NORTH,
}
add(mapping[c, direction], pos)
return len(covered)
print(solve(inp, (Dir.EAST, (0, 0))))
p2 = 0
for x in range(len(inp[0])):
p2 = max(p2, solve(inp, (Dir.SOUTH, (x, 0))))
p2 = max(p2, solve(inp, (Dir.NORTH, (x, len(inp)))))
for y in range(len(inp)):
p2 = max(p2, solve(inp, (Dir.EAST, (0, y))))
p2 = max(p2, solve(inp, (Dir.WEST, (len(inp[0]), y))))
print(p2)
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