View Compilation Error

0_0_29995402_171.cpp: In function 'void bfs()':
0_0_29995402_171.cpp:23:2: error: 'priority_queue' was not declared in this scope
  priority_queue<node> q;
  ^
0_0_29995402_171.cpp:23:21: error: expected primary-expression before '>' token
  priority_queue<node> q;
                     ^
0_0_29995402_171.cpp:23:23: error: 'q' was not declared in this scope
  priority_queue<node> q;
                       ^