Perl, 144 138 132 129 128 127 126 124 байта
Включает +2 для -p0
Код предполагает, \0
что не является допустимым символом ввода (по крайней мере, внутри #
).
Запустите с помощью ввода на STDIN:
surround.pl < surround.txt
surround.pl
:
#!/usr/bin/perl -p0
/^#[^#\0]/m&&s/^|[^#\n\0]\0/\0\0/mg,s%.%s/.(.*)/$+\0/g;/#/&&reverse"\n",/^./mg%seg until$?++<$$_++;y/\0/#/;s/^#*\n|#+$|^#//mg;y;#;
Код работает как есть, но замените их \0
и \n
их буквальными версиями для заявленной оценки. Обратите внимание, что
в конце строки есть пробел . Код зацикливается слишком много раз, поэтому вам, возможно, придется ждать около 30 секунд для вывода.
объяснение
Я собираюсь сделать заливку с \0
остановленным #
извне в ортогональных направлениях. После этого я срежу по #
бокам и заменю все, что осталось пробелами. Чтобы избежать необходимости обрабатывать все направления в заливке, я буду многократно вращать целевую область и выполнять заливку только справа налево.
/^#[^#\0]/m The rotation is written such that it slices
off the first column. That is ok unless the
first column contains a # that is followed by
something that could be the inside. There is
no newline inside the [] because short lines
will get extended during the rotation and
the character following the # will end
up as a \0 and match in a later round
&&s/^|[^#\n\0]\0/\0\0/mg In case the # could be an interior border I
will add two columns of \0's in front. One
will be a sacrifice for the rotation, the
other column will end up at the end of the area
after two rotations and function as seed for the
floodfill. This regex also does one step of
the floodfill from the back to the front.
After a certain number of loops we are certain
to get to a first column that must not be
dropped so at some point the last column is
guaranteed to consist of only \0. And we only need
to fill backward since the rotations will make
any direction backward at some point
s%.% process column %seg I will replace each character (including \n)
in the string by the next column in reversed
order or an empty string if there are no more
interesting columns. This is therefore a right
rotation. There are less columns than
characters so this loop is long enough
s%.%s/.(.*)/$+\0/g Remove the next (now first) character from each
row (so remove the column). Because the
original area is not necessarily a rectangle
add a \0 at the end of the row so we won't run
out out of columns (this would cause shorter
rows to have no entry in the new rotated row)
This will not do anything for empty lines so
they DO get squeezed out. But that is not a
problem since the problem statement says there
will be only one # shape so any empty lines
are can be safely dropped (this would not be
so if there could be multiple # shapes because
that could create a new surrounded area
/#/ Check if any of the remaining columns still
has a #. If not all remaining columns are on
the outside and can be dropped
&&reverse"\n",/^./mg Collect the column and add a \n to its reverse
until$?++<$$_++ Keep doing this until we get to a multiple of
65536 rotations when $? waraps back around to 0
(this is a multiple of 4 so the area is left
unrotated) and an area we have seen before
($$_ >= 1)
(so all slicing and flood filling is finished)
$_ having been seen in a previous rotations is
not a problem (though rather tricky to prove)
На данный момент, например,
AB##J
E####GK
F# M #L
# N#O
P####
будет заменен на:
0000000
0####00
0# M #0
# N#0
0####00
В основном все столбцы и строки, которые непосредственно не граничат с внутренней частью, были обрезаны. Все оставшиеся внешние символы были заменены на \ 0. Вверху и справа есть дополнительный слой \ 0. Так что все, что осталось, это очистить:
y/\0/#/ Replace any outside that is left by #
s/^#*\n|#+$|^#//mg Removes the first two and last line (the only
lines that can consist of purely #)
Removes any trailing #
Removes the first column of #
y;#; \n; Replace any remaining # by space since they
are needed to fill the concave parts
The final \n; is not written since it is implicit
in the -p loop
#
s и там вы идете ... а потом стало трудно.