equivalent of int[] + k on vector in c++

Question

I have an algorithm and I'd like to translate my code so instead of using arrays I'd like to use vectors.

How would you translate this: (the side of b + j and a)

find_kth(a, b + j, i, size_b - j, k - j);

where

int find_kth(int a[], int b[], int size_a, int size_b, int k);

into

int find_kth(const vector<int>& a, const vector<int>& b, int size_a, int size_b, int k);

It must be equivalent so calls like this return the same value as if I were using arrays:

min(a[0], b[0]);

Answer 1

A standard way would be to use iterator ranges instead:

template <typename Iterator>
int find_kth(
    Iterator a_begin,
    Iterator a_end,
    Iterator b_begin,
    Iterator b_end,
    int k);

This comes in handy, since you need to operate only on a section of a vector. You don't need to split the vector with this approach.

Improved signature based on SergeyA's comment:

template <typename T>
using is_fwd_it = std::is_base_of<
    std::forward_iterator_tag,
    typename std::iterator_traits<T>::iterator_category>;

template <typename A_It, typename B_It,
    typename = typename std::enable_if<
        is_fwd_it<A_It>::value && is_fwd_it<B_It>::value>::type>
int find_kth(
    A_It a_begin,
    A_It a_end,
    B_It b_begin,
    B_It b_end,
    int k);

You can also add another template parameter, or use std::iterator_traits to get the value_type, instead of having int.