View Compilation Error

0_0_28776881_5538.cpp: In function 'int main()':
0_0_28776881_5538.cpp:46:9: error: 'queue' was not declared in this scope
         queue<int> Q;
         ^
0_0_28776881_5538.cpp:46:15: error: expected primary-expression before 'int'
         queue<int> Q;
               ^
0_0_28776881_5538.cpp:49:18: error: 'Q' was not declared in this scope
                 {Q.push(i); cost[i] = 1;}
                  ^
0_0_28776881_5538.cpp:52:16: error: 'Q' was not declared in this scope
         while(!Q.empty())
                ^