View Compilation Error

0_0_25118663_29703.cpp: In function 'bool spfa()':
0_0_25118663_29703.cpp:22:2: error: 'queue' was not declared in this scope
  queue<int>qu;
  ^
0_0_25118663_29703.cpp:22:8: error: expected primary-expression before 'int'
  queue<int>qu;
        ^
0_0_25118663_29703.cpp:29:5: error: 'qu' was not declared in this scope
     qu.push(s);
     ^