I guess the "replace" operation takes more time than a solution with a single pass over the string

Nice

can you explain your solution?

Yes, this repetitive process makes it a slow solution.

I upvote for clever, but terribly slow.

line 7 and 8 are totally random, i was just making an experiment.
suddenly, it did not time out.
i deleted those, and again I was out of time. and then accidentaly I submitted this...

this will work until the data inside the brackets appears.

don't worry, you're not responsible in any way (well, almost x) )

;)

sorry about that, i was just happy i found a solution under a minute. now i see it is not the fastest one..

you're not missing anything, except noobs upvoting this solution ;)

O(N²)...

krasava