/in/foo.cc:3:1: error: 'priority_queue' does not name a type
 priority_queue < int,vector<int>,greater<int> > q;
 ^~~~~~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:11:8: error: 'q' was not declared in this scope
        q.push(k);
        ^
/in/foo.cc:15:10: error: 'q' was not declared in this scope
        a=q.top();
          ^