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
cnexans:
20160730 21:45:38
Easy question nonetheless you might get WA because of getline or gets. Hint: you do it everytime you program. No need for stacks. 

nandhan:
20160720 20:16:16
how the output is 1 for this case "{{{}" ?? 

adi_1996:
20160705 12:53:02
O(n) without stack !1 :)


blackjack123:
20160704 23:16:44
that was odd right... 

sonali9696:
20160630 22:59:19
What about cases like {}{ > how to make such braces stable by just substitution?


baadshah_:
20160627 16:51:14
AC in One GO!!! O(n)Time O(1) Space 

ianand:
20160609 09:29:07
No need of dp simple question.


Laurensius Adi:
20160527 21:03:49
How to solve this problem using dp? 

ajay_5097:
20160414 21:11:06
one silly mistake !!


vsp4:
20160329 07:16:45
Using getline(cin, str) gives WA. But with scanf it gets AC. Huh? 
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 