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
amitnsky:
20180906 18:21:21
using stack will also give you correct ans becoz


logic_bomb:
20180729 07:50:10
Last edit: 20180729 07:56:32 

the_ashutosh:
20180701 12:53:35
Why is it tagged DP????? 

soham_12345:
20180617 15:59:20
Use getline to read input. Adhoc solution is possible. But those who want to know how to solve using dp the states are dp(n,unbalance), where n is my current index and unbalance is unbalance upto current index. One can easily prove that adhoc solution is correct indeed. 

anshuman1117:
20180611 17:12:12
AC in 1 go is easily possible with a stack. Even without a stack, simply taking the count of brackets can easily solve this problem. Very trivial problem. No need to waste time in getting a DP solution working :) 

kkislay20:
20180607 13:40:45
Can anyone tell me how to solve it using dp??


dsri_99:
20180606 12:27:32
@puru it's given that length of the string is even


puru299792458:
20180604 20:14:16
what should be the output of {}{ 

ronak66:
20180517 14:17:45
can anyone provide me a test case where there is a possibility of wrong answer?? 

shashankpathak:
20180513 16:37:47
Good question on stack

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 