Remove duplicates vector from vector of vector

I am trying to implement the solution to the problem found at Link.

Here is my snippet of code

bool compareVec(vector<int> a, vector<int> b) {
    return std::equal(a.begin(), a.end(), b.begin());
}
vector<vector<int> > ans;
ans.erase(std::remove_if(ans.begin(), ans.end(), compareVec), ans.end());

I am getting the following errors

/usr/include/c++/4.8/bits/stl_algo.h: In instantiation of 
'_RandomAccessIterator std::__find_if(_RandomAccessIterator, 
_RandomAccessIterator, _Predicate, std::random_access_iterator_tag) [with 
_RandomAccessIterator = __gnu_cxx::__normal_iterator<std::vector<int>*, 
std::vector<std::vector<int> > >; _Predicate = bool (*)(std::vector<int>, 
std::vector<int>)]':

/usr/include/c++/4.8/bits/stl_algo.h:4465:41:   required from '_IIter   
std::find_if(_IIter, _IIter, _Predicate) [with _IIter = 
__gnu_cxx::__normal_iterator<std::vector<int>*, std::vector<std::vector<int>
 > >; _Predicate = bool (*)(std::vector<int>, std::vector<int>)]'

/usr/include/c++/4.8/bits/stl_algo.h:1144:64:   required from '_FIter 
std::remove_if(_FIter, _FIter, _Predicate) [with _FIter = 
__gnu_cxx::__normal_iterator<std::vector<int>*, std::vector<std::vector<int> 
> >; _Predicate = bool (*)(std::vector<int>, std::vector<int>)]'

solution.cpp:40:64:   required from here
/usr/include/c++/4.8/bits/stl_algo.h:214:23: error: too few arguments to    
function
if (__pred(*__first))
                   ^
/usr/include/c++/4.8/bits/stl_algo.h:218:23: error: too few arguments to   
function
if (__pred(*__first))
                   ^
/usr/include/c++/4.8/bits/stl_algo.h:222:23: error: too few arguments to 
function
if (__pred(*__first))
                   ^

Can anyone help me out in debugging this? Thanks in advance

EDIT

The elements of vector are sorted and all these vectors are also sorted.

Unique also gives an error. I am unable to figure out why?

Why is the example given in the link I provided, not helpful here?