ANARC09A  Seinfeld
I’m out of stories. For years I’ve been writing stories, some rather silly, just to make simple problems look difficult and complex problems look easy. But, alas, not for this one.
You’re given a non empty string made in its entirety from opening and closing braces. Your task is to find the minimum number of “operations” needed to make the string stable. The definition for being stable is as follows:
 An empty string is stable.
 If S is stable, then {S} is also stable.
 If S and T are both stable, then ST (the concatenation of the two) is also stable.
All of these strings are stable: {}, {}{}, and {{}{}}; But none of these: }{, {{}{, nor {}{.
The only operation allowed on the string is to replace an opening brace with a closing brace, or visaversa.
Input
Your program will be tested on one or more data sets. Each data set is described on a single line. The line is a nonempty string of opening and closing braces and nothing else. No string has more than 2000 braces. All sequences are of even length.
The last line of the input is made of one or more ’’ (minus signs.)
Output
For each test case, print the following line:
k. N
Where k is the test case number (starting at one,) and N is the minimum number of operations needed to convert the given string into a balanced one.
Example
Input: }{
{}{}{}
{{{}

Output: 1. 2
2. 0
3. 1
hide comments
sk128:
20210814 09:16:22
No stack or DP needed ; just traverse the string once with few count variables . 

Waseem Ahmed:
20210630 21:11:49
Simple problem suing stack. Hint : Eliminate all the matching braces and then consider the remaining braces. How many variations can you see?


tropo_sphere:
20210627 09:08:00
im gettin wa looking fr a testcase 

yasser1110:
20210618 17:37:37
Downvoted the problem, simply because input consists of non brace characters, (maybe whitespaces), even though the question clearly says that only open and close braces are a part of the input. Also incorrectly tagged. Its not DP.


saurabhs_09:
20210614 14:08:01
what will be input format??


spojmagyan:
20210529 17:12:03
if in input there is no k, how to display it ? 

anupam_akib:
20210519 21:08:03
AC in one go using greedy approach. Can someone please give me some hints for solving it in DP? 

sharma_swati:
20210509 16:51:54
does it contain only curly braces or all other types of braces also?


jajopi:
20210324 17:28:43
Nice simple problem, there is no need for DP neither Stack (just think about how many different things would you put inside). The hardest part is to not forget the output format :D 

toki_64_vaiya:
20210211 15:05:41
Gave me TLE.

Added by:  Mohammad Kotb 
Date:  20091128 
Time limit:  3.236s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All except: ASM64 BASH JSRHINO 
Resource:  http://www.icpcanarc.org 