View Compilation Error

0_0_29443909_18787.cpp:20:12: error: variable or field 'trans' declared void
 void trans(vector<int>& p, int o){
            ^
0_0_29443909_18787.cpp:20:12: error: 'vector' was not declared in this scope
0_0_29443909_18787.cpp:20:19: error: expected primary-expression before 'int'
 void trans(vector<int>& p, int o){
                   ^
0_0_29443909_18787.cpp:20:28: error: expected primary-expression before 'int'
 void trans(vector<int>& p, int o){
                            ^