View Compilation Error

0_0_37724811_12126.cpp:11:17: error: '__gnu_pbds' is not a namespace-name
 using namespace __gnu_pbds; ////priority_queue有冲突空间
                 ^
0_0_37724811_12126.cpp:11:27: error: expected namespace-name before ';' token
 using namespace __gnu_pbds; ////priority_queue有冲突空间
                           ^
0_0_37724811_12126.cpp:15:5: error: 'tree' does not name a type
     tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
     ^