View Compilation Error

0_0_39709566_12156.cpp: In function 'int main()':
0_0_39709566_12156.cpp:21:41: error: template argument 1 is invalid
   21 |         priority_queue<pair<int,int> q[4];
      |                                         ^
0_0_39709566_12156.cpp:21:41: error: template argument 2 is invalid
0_0_39709566_12156.cpp:21:41: error: template argument 3 is invalid
0_0_39709566_12156.cpp:28:17: error: 'q' was not declared in this scope
   28 |                 q[b].push({c,-i});
      |                 ^
0_0_39709566_12156.cpp:32:21: error: 'q' was not declared in this scope
   32 |                 if(!q[b].empty()){
      |                     ^