DouKaku?

#include <iostream>
#include <vector>
#include <algorithm>
#include <iterator>

template <typename ForwardIterator>
ForwardIterator uniq(ForwardIterator beg, ForwardIterator end)
{
    while (beg != end)
    {
        ForwardIterator cur = beg++;

        end = std::remove(beg, end, *cur);
    }

    return end;
}

int main()
{
    const int a[] = {3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5, 8, 9, 7, 9};

    std::vector<int> v(a, a + sizeof(a) / sizeof(*a));

    v.erase(uniq(v.begin(), v.end()), v.end());

    std::copy(v.begin(), v.end(), std::ostream_iterator<int>(std::cout, " "));
}