View Compilation Error

0_0_28483887_9260.cpp:14:1: error: 'queue' does not name a type
 queue<int>q;
 ^
0_0_28483887_9260.cpp: In function 'int main()':
0_0_28483887_9260.cpp:17:25: error: 'stdin' was not declared in this scope
     freopen("i.txt","r",stdin);
                         ^
0_0_28483887_9260.cpp:17:30: error: 'freopen' was not declared in this scope
     freopen("i.txt","r",stdin);
                              ^
0_0_28483887_9260.cpp:19:18: error: 'scanf' was not declared in this scope
     scanf("%d",&T);
                  ^
0_0_28483887_9260.cpp:22:35: error: 'memset' was not declared in this scope
         memset(head,-1,sizeof head);
                                   ^
0_0_28483887_9260.cpp:32:9: error: 'q' was not declared in this scope
         q.push(1);
         ^
0_0_28483887_9260.cpp:63:31: error: 'max' was not declared in this scope
             ans=max(vis[v],ans);
                               ^
0_0_28483887_9260.cpp:74:9: error: 'cout' was not declared in this scope
         cout<<ans<<endl;
         ^
0_0_28483887_9260.cpp:74:20: error: 'endl' was not declared in this scope
         cout<<ans<<endl;
                    ^