/in/compress.cpp:2:36: error: 'vector' does not name a type
 std::vector<node_t> compress(const vector<int>& m)
                                    ^~~~~~
/in/compress.cpp:2:42: error: expected ',' or '...' before '<' token
 std::vector<node_t> compress(const vector<int>& m)
                                          ^
/in/compress.cpp: In function 'std::vector<node_t> compress(int)':
/in/compress.cpp:4:5: error: 'vector' was not declared in this scope
     vector<node_t> a;
     ^~~~~~
/in/compress.cpp:4:5: note: suggested alternative:
In file included from /usr/include/c++/7/vector:64:0,
                 from /in/compile/compress.h:4,
                 from /in/compress.cpp:1:
/usr/include/c++/7/bits/stl_vector.h:216:11: note:   'std::vector'
     class vector : protected _Vector_base<_Tp, _Alloc>
           ^~~~~~
/in/compress.cpp:4:18: error: expected primary-expression before '>' token
     vector<node_t> a;
                  ^
/in/compress.cpp:4:20: error: 'a' was not declared in this scope
     vector<node_t> a;
                    ^
/in/compress.cpp:5:8: error: 'm' was not declared in this scope
     if(m.size()==0)
        ^