Main.cc: In function ‘void solve()’:
Main.cc:9:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i = 0 ; i < str.size() ; i++ )
~~^~~~~~~~~~~~
Main.cc:12:19: error: invalid operands of types ‘’ and ‘char’ to binary ‘operator==’
if(s.top == '{') s.pop() ;
~~~~~~^~~~~~
Main.cc:15:19: error: invalid operands of types ‘’ and ‘char’ to binary ‘operator==’
if(s.top == ']') s.pop() ;
~~~~~~^~~~~~
Main.cc:18:19: error: invalid operands of types ‘’ and ‘char’ to binary ‘operator==’
if(s.top == '(') s.pop() ;
~~~~~~^~~~~~
Main.cc:21:19: error: invalid operands of types ‘’ and ‘char’ to binary ‘operator==’
if(s.top == '<') s.pop() ;
~~~~~~^~~~~~