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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3. #define GG ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
  4. int main () { GG;
  5. string s;
  6. cin>>s;	int n=s.size(),ans=0;
  7. stack <char> st;	bool f=0;
  8.  
  9. for(int i=0;i<n;i++)
  10. {	if(  (s[i]=='(' ) || (s[i]=='{' ) || (s[i]=='[' ) || (s[i]=='<' )   )
  11. 	st.push(s[i]);
  12. 	else if(st.size() != 0)
  13. 	{	if ( st.top()=='(' && s[i]==')')
  14. 		st.pop();
  15. 		else if(st.top()=='{' && s[i]=='}')
  16. 		st.pop();
  17. 		else if(st.top()=='[' && s[i]==']')
  18. 		st.pop();
  19. 		else if(st.top()=='<' && s[i]=='>')
  20. 		st.pop();
  21.  
  22. 		else
  23. 		{ st.pop();
  24. 		  ans++;
  25. 		}
  26. 	}
  27. 	else
  28. 	{ f=1; break;
  29. 	}
  30. }
  31.  
  32. if(f || st.size()!=0 )	cout<<"Impossible\n";
  33. else	cout<<ans<<"\n";
  34. return 0;}
Success #stdin #stdout 0.01s 5308KB
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Impossible
https://ideone.com/RUnS0t
language:
C++ (gcc 8.3)
created:
17 days ago
visibility:
public

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