View Compilation Error

0_0_25385065_31003.cpp: In function 'int main()':
0_0_25385065_31003.cpp:20:3: error: 'priority_queue' was not declared in this scope
   priority_queue<int,vector<int>,greater<int> >q;
   ^
0_0_25385065_31003.cpp:20:18: error: expected primary-expression before 'int'
   priority_queue<int,vector<int>,greater<int> >q;
                  ^
0_0_25385065_31003.cpp:21:10: error: 'q' was not declared in this scope
   while(!q.empty())q.pop();
          ^
0_0_25385065_31003.cpp:22:24: error: 'q' was not declared in this scope
   for(int i=1;i<=N;++i)q.push(i);
                        ^
0_0_25385065_31003.cpp:33:11: error: 'q' was not declared in this scope
    ans[i]=q.top();
           ^
0_0_25385065_31003.cpp:40:17: error: 'q' was not declared in this scope
     if(ans[cur])q.push(ans[cur]);//reuse
                 ^
0_0_25385065_31003.cpp:43:13: error: 'q' was not declared in this scope
      ans[j]=q.top();q.pop();
             ^
0_0_25385065_31003.cpp:47:13: error: 'q' was not declared in this scope
      ans[j]=q.top();
             ^