|
|
|
|
tiles = DATA.readlines(chomp: true).flat_map.with_index {|row, y|
|
|
|
|
|
row.chars.filter_map.with_index {|tile, x|
|
|
|
|
|
tile == ?# ? nil : [[y,x], tile]
|
|
|
|
|
}
|
|
|
|
|
}.to_h
|
|
|
|
|
|
|
|
|
|
start, stop = %w[ S E ].map {|t| tiles.find { _2 == t }[0] }
|
|
|
|
|
|
|
|
|
|
scores = Hash.new(Float::INFINITY)
|
|
|
|
|
scores[[start, [0,1]]] = 0
|
|
|
|
|
|
|
|
|
|
queue = [[start, [0,1]]]
|
|
|
|
|
visited = Set.new
|
|
|
|
|
loop do
|
|
|
|
|
fail if queue.empty?
|
|
|
|
|
|
|
|
|
|
current, dir = queue.shift
|
|
|
|
|
visited << [current, dir]
|
|
|
|
|
score = scores.fetch([current, dir])
|
|
|
|
|
break if current == stop
|
|
|
|
|
|
|
|
|
|
# straight ahead
|
|
|
|
|
yx = current.zip(dir).map { _1 + _2 }
|
|
|
|
|
if tiles.has_key?(yx)
|
|
|
|
|
scores[[yx, dir]] = [scores[[yx, dir]], score + 1].min
|
|
|
|
|
queue << [yx, dir] unless visited.include?([yx, dir])
|
|
|
|
|
end
|
|
|
|
|
|
|
|
|
|
# sides
|
|
|
|
|
[-1, 1].each do |d|
|
|
|
|
|
delta = dir.reverse.zip([d, d]).map { _1 * _2 }
|
|
|
|
|
yx = current.zip(delta).map { _1 + _2 }
|
|
|
|
|
if tiles.has_key?(yx)
|
|
|
|
|
scores[[yx, delta]] = [scores[[yx, delta]], score + 1001].min
|
|
|
|
|
queue << [yx, delta] unless visited.include?([yx, delta])
|
|
|
|
|
end
|
|
|
|
|
end
|
|
|
|
|
|
|
|
|
|
queue.uniq!
|
|
|
|
|
queue.sort_by! { scores.fetch(_1) }
|
|
|
|
|
end
|
|
|
|
|
|
|
|
|
|
pp scores.find {|(yx,_),_| yx == stop }[1]
|
|
|
|
|
|
|
|
|
|
__END__
|
|
|
|
|
###############
|
|
|
|
|
#.......#....E#
|
|
|
|
|
#.#.###.#.###.#
|
|
|
|
|
#.....#.#...#.#
|
|
|
|
|
#.###.#####.#.#
|
|
|
|
|
#.#.#.......#.#
|
|
|
|
|
#.#.#####.###.#
|
|
|
|
|
#...........#.#
|
|
|
|
|
###.#.#####.#.#
|
|
|
|
|
#...#.....#.#.#
|
|
|
|
|
#.#.#.###.#.#.#
|
|
|
|
|
#.....#...#.#.#
|
|
|
|
|
#.###.#.#.#.#.#
|
|
|
|
|
#S..#.....#...#
|
|
|
|
|
###############
|
