//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

// <algorithm>

// template<InputIterator InIter1, InputIterator InIter2, typename OutIter,
//          CopyConstructible Compare>
//   requires OutputIterator<OutIter, InIter1::reference>
//         && OutputIterator<OutIter, InIter2::reference>
//         && Predicate<Compare, InIter1::value_type, InIter2::value_type>
//         && Predicate<Compare, InIter2::value_type, InIter1::value_type>
//   constpexr OutIter       // constexpr after C++17
//   set_intersection(InIter1 first1, InIter1 last1, InIter2 first2, InIter2 last2,
//                    OutIter result, Compare comp);

#include <algorithm>
#include <functional>
#include <cassert>

#include "test_macros.h"
#include "test_iterators.h"

#if TEST_STD_VER > 17
TEST_CONSTEXPR bool test_constexpr() {
    const int ia[] = {1, 2, 2, 3, 3, 3, 4, 4, 4, 4};
    const int ib[] = {2, 4, 4, 6};
          int results[std::size(ia)] = {0};

    auto comp = [](int a, int b) {return a < b; };
    auto it = std::set_intersection(std::begin(ia), std::end(ia),
                                    std::begin(ib), std::end(ib), std::begin(results), comp);

    return std::includes(std::begin(ia), std::end(ia), std::begin(results), it)
        && std::includes(std::begin(ib), std::end(ib), std::begin(results), it)
        && std::is_sorted(std::begin(results), it, comp)
        && std::all_of(it, std::end(results), [](int a) {return a == 0; })
           ;
    }
#endif


template <class Iter1, class Iter2, class OutIter>
void
test()
{
    int ia[] = {1, 2, 2, 3, 3, 3, 4, 4, 4, 4};
    const int sa = sizeof(ia)/sizeof(ia[0]);
    int ib[] = {2, 4, 4, 6};
    const int sb = sizeof(ib)/sizeof(ib[0]);
    int ic[20];
    int ir[] = {2, 4, 4};
    const int sr = sizeof(ir)/sizeof(ir[0]);
    OutIter ce = std::set_intersection(Iter1(ia), Iter1(ia+sa),
                                       Iter2(ib), Iter2(ib+sb), OutIter(ic), std::less<int>());
    assert(base(ce) - ic == sr);
    assert(std::lexicographical_compare(ic, base(ce), ir, ir+sr) == 0);
    ce = std::set_intersection(Iter1(ib), Iter1(ib+sb),
                               Iter2(ia), Iter2(ia+sa), OutIter(ic), std::less<int>());
    assert(base(ce) - ic == sr);
    assert(std::lexicographical_compare(ic, base(ce), ir, ir+sr) == 0);
}

int main(int, char**)
{
    test<input_iterator<const int*>, input_iterator<const int*>, output_iterator<int*> >();
    test<input_iterator<const int*>, input_iterator<const int*>, forward_iterator<int*> >();
    test<input_iterator<const int*>, input_iterator<const int*>, bidirectional_iterator<int*> >();
    test<input_iterator<const int*>, input_iterator<const int*>, random_access_iterator<int*> >();
    test<input_iterator<const int*>, input_iterator<const int*>, int*>();

    test<input_iterator<const int*>, forward_iterator<const int*>, output_iterator<int*> >();
    test<input_iterator<const int*>, forward_iterator<const int*>, forward_iterator<int*> >();
    test<input_iterator<const int*>, forward_iterator<const int*>, bidirectional_iterator<int*> >();
    test<input_iterator<const int*>, forward_iterator<const int*>, random_access_iterator<int*> >();
    test<input_iterator<const int*>, forward_iterator<const int*>, int*>();

    test<input_iterator<const int*>, bidirectional_iterator<const int*>, output_iterator<int*> >();
    test<input_iterator<const int*>, bidirectional_iterator<const int*>, forward_iterator<int*> >();
    test<input_iterator<const int*>, bidirectional_iterator<const int*>, bidirectional_iterator<int*> >();
    test<input_iterator<const int*>, bidirectional_iterator<const int*>, random_access_iterator<int*> >();
    test<input_iterator<const int*>, bidirectional_iterator<const int*>, int*>();

    test<input_iterator<const int*>, random_access_iterator<const int*>, output_iterator<int*> >();
    test<input_iterator<const int*>, random_access_iterator<const int*>, forward_iterator<int*> >();
    test<input_iterator<const int*>, random_access_iterator<const int*>, bidirectional_iterator<int*> >();
    test<input_iterator<const int*>, random_access_iterator<const int*>, random_access_iterator<int*> >();
    test<input_iterator<const int*>, random_access_iterator<const int*>, int*>();

    test<input_iterator<const int*>, const int*, output_iterator<int*> >();
    test<input_iterator<const int*>, const int*, forward_iterator<int*> >();
    test<input_iterator<const int*>, const int*, bidirectional_iterator<int*> >();
    test<input_iterator<const int*>, const int*, random_access_iterator<int*> >();
    test<input_iterator<const int*>, const int*, int*>();

    test<forward_iterator<const int*>, input_iterator<const int*>, output_iterator<int*> >();
    test<forward_iterator<const int*>, input_iterator<const int*>, forward_iterator<int*> >();
    test<forward_iterator<const int*>, input_iterator<const int*>, bidirectional_iterator<int*> >();
    test<forward_iterator<const int*>, input_iterator<const int*>, random_access_iterator<int*> >();
    test<forward_iterator<const int*>, input_iterator<const int*>, int*>();

    test<forward_iterator<const int*>, forward_iterator<const int*>, output_iterator<int*> >();
    test<forward_iterator<const int*>, forward_iterator<const int*>, forward_iterator<int*> >();
    test<forward_iterator<const int*>, forward_iterator<const int*>, bidirectional_iterator<int*> >();
    test<forward_iterator<const int*>, forward_iterator<const int*>, random_access_iterator<int*> >();
    test<forward_iterator<const int*>, forward_iterator<const int*>, int*>();

    test<forward_iterator<const int*>, bidirectional_iterator<const int*>, output_iterator<int*> >();
    test<forward_iterator<const int*>, bidirectional_iterator<const int*>, forward_iterator<int*> >();
    test<forward_iterator<const int*>, bidirectional_iterator<const int*>, bidirectional_iterator<int*> >();
    test<forward_iterator<const int*>, bidirectional_iterator<const int*>, random_access_iterator<int*> >();
    test<forward_iterator<const int*>, bidirectional_iterator<const int*>, int*>();

    test<forward_iterator<const int*>, random_access_iterator<const int*>, output_iterator<int*> >();
    test<forward_iterator<const int*>, random_access_iterator<const int*>, forward_iterator<int*> >();
    test<forward_iterator<const int*>, random_access_iterator<const int*>, bidirectional_iterator<int*> >();
    test<forward_iterator<const int*>, random_access_iterator<const int*>, random_access_iterator<int*> >();
    test<forward_iterator<const int*>, random_access_iterator<const int*>, int*>();

    test<forward_iterator<const int*>, const int*, output_iterator<int*> >();
    test<forward_iterator<const int*>, const int*, forward_iterator<int*> >();
    test<forward_iterator<const int*>, const int*, bidirectional_iterator<int*> >();
    test<forward_iterator<const int*>, const int*, random_access_iterator<int*> >();
    test<forward_iterator<const int*>, const int*, int*>();

    test<bidirectional_iterator<const int*>, input_iterator<const int*>, output_iterator<int*> >();
    test<bidirectional_iterator<const int*>, input_iterator<const int*>, bidirectional_iterator<int*> >();
    test<bidirectional_iterator<const int*>, input_iterator<const int*>, bidirectional_iterator<int*> >();
    test<bidirectional_iterator<const int*>, input_iterator<const int*>, random_access_iterator<int*> >();
    test<bidirectional_iterator<const int*>, input_iterator<const int*>, int*>();

    test<bidirectional_iterator<const int*>, forward_iterator<const int*>, output_iterator<int*> >();
    test<bidirectional_iterator<const int*>, forward_iterator<const int*>, forward_iterator<int*> >();
    test<bidirectional_iterator<const int*>, forward_iterator<const int*>, bidirectional_iterator<int*> >();
    test<bidirectional_iterator<const int*>, forward_iterator<const int*>, random_access_iterator<int*> >();
    test<bidirectional_iterator<const int*>, forward_iterator<const int*>, int*>();

    test<bidirectional_iterator<const int*>, bidirectional_iterator<const int*>, output_iterator<int*> >();
    test<bidirectional_iterator<const int*>, bidirectional_iterator<const int*>, forward_iterator<int*> >();
    test<bidirectional_iterator<const int*>, bidirectional_iterator<const int*>, bidirectional_iterator<int*> >();
    test<bidirectional_iterator<const int*>, bidirectional_iterator<const int*>, random_access_iterator<int*> >();
    test<bidirectional_iterator<const int*>, bidirectional_iterator<const int*>, int*>();

    test<bidirectional_iterator<const int*>, random_access_iterator<const int*>, output_iterator<int*> >();
    test<bidirectional_iterator<const int*>, random_access_iterator<const int*>, forward_iterator<int*> >();
    test<bidirectional_iterator<const int*>, random_access_iterator<const int*>, bidirectional_iterator<int*> >();
    test<bidirectional_iterator<const int*>, random_access_iterator<const int*>, random_access_iterator<int*> >();
    test<bidirectional_iterator<const int*>, random_access_iterator<const int*>, int*>();

    test<bidirectional_iterator<const int*>, const int*, output_iterator<int*> >();
    test<bidirectional_iterator<const int*>, const int*, forward_iterator<int*> >();
    test<bidirectional_iterator<const int*>, const int*, bidirectional_iterator<int*> >();
    test<bidirectional_iterator<const int*>, const int*, random_access_iterator<int*> >();
    test<bidirectional_iterator<const int*>, const int*, int*>();

    test<random_access_iterator<const int*>, input_iterator<const int*>, output_iterator<int*> >();
    test<random_access_iterator<const int*>, input_iterator<const int*>, bidirectional_iterator<int*> >();
    test<random_access_iterator<const int*>, input_iterator<const int*>, bidirectional_iterator<int*> >();
    test<random_access_iterator<const int*>, input_iterator<const int*>, random_access_iterator<int*> >();
    test<random_access_iterator<const int*>, input_iterator<const int*>, int*>();

    test<random_access_iterator<const int*>, forward_iterator<const int*>, output_iterator<int*> >();
    test<random_access_iterator<const int*>, forward_iterator<const int*>, forward_iterator<int*> >();
    test<random_access_iterator<const int*>, forward_iterator<const int*>, bidirectional_iterator<int*> >();
    test<random_access_iterator<const int*>, forward_iterator<const int*>, random_access_iterator<int*> >();
    test<random_access_iterator<const int*>, forward_iterator<const int*>, int*>();

    test<random_access_iterator<const int*>, bidirectional_iterator<const int*>, output_iterator<int*> >();
    test<random_access_iterator<const int*>, bidirectional_iterator<const int*>, forward_iterator<int*> >();
    test<random_access_iterator<const int*>, bidirectional_iterator<const int*>, bidirectional_iterator<int*> >();
    test<random_access_iterator<const int*>, bidirectional_iterator<const int*>, random_access_iterator<int*> >();
    test<random_access_iterator<const int*>, bidirectional_iterator<const int*>, int*>();

    test<random_access_iterator<const int*>, random_access_iterator<const int*>, output_iterator<int*> >();
    test<random_access_iterator<const int*>, random_access_iterator<const int*>, forward_iterator<int*> >();
    test<random_access_iterator<const int*>, random_access_iterator<const int*>, bidirectional_iterator<int*> >();
    test<random_access_iterator<const int*>, random_access_iterator<const int*>, random_access_iterator<int*> >();
    test<random_access_iterator<const int*>, random_access_iterator<const int*>, int*>();

    test<random_access_iterator<const int*>, const int*, output_iterator<int*> >();
    test<random_access_iterator<const int*>, const int*, forward_iterator<int*> >();
    test<random_access_iterator<const int*>, const int*, bidirectional_iterator<int*> >();
    test<random_access_iterator<const int*>, const int*, random_access_iterator<int*> >();
    test<random_access_iterator<const int*>, const int*, int*>();

    test<const int*, input_iterator<const int*>, output_iterator<int*> >();
    test<const int*, input_iterator<const int*>, bidirectional_iterator<int*> >();
    test<const int*, input_iterator<const int*>, bidirectional_iterator<int*> >();
    test<const int*, input_iterator<const int*>, random_access_iterator<int*> >();
    test<const int*, input_iterator<const int*>, int*>();

    test<const int*, forward_iterator<const int*>, output_iterator<int*> >();
    test<const int*, forward_iterator<const int*>, forward_iterator<int*> >();
    test<const int*, forward_iterator<const int*>, bidirectional_iterator<int*> >();
    test<const int*, forward_iterator<const int*>, random_access_iterator<int*> >();
    test<const int*, forward_iterator<const int*>, int*>();

    test<const int*, bidirectional_iterator<const int*>, output_iterator<int*> >();
    test<const int*, bidirectional_iterator<const int*>, forward_iterator<int*> >();
    test<const int*, bidirectional_iterator<const int*>, bidirectional_iterator<int*> >();
    test<const int*, bidirectional_iterator<const int*>, random_access_iterator<int*> >();
    test<const int*, bidirectional_iterator<const int*>, int*>();

    test<const int*, random_access_iterator<const int*>, output_iterator<int*> >();
    test<const int*, random_access_iterator<const int*>, forward_iterator<int*> >();
    test<const int*, random_access_iterator<const int*>, bidirectional_iterator<int*> >();
    test<const int*, random_access_iterator<const int*>, random_access_iterator<int*> >();
    test<const int*, random_access_iterator<const int*>, int*>();

    test<const int*, const int*, output_iterator<int*> >();
    test<const int*, const int*, forward_iterator<int*> >();
    test<const int*, const int*, bidirectional_iterator<int*> >();
    test<const int*, const int*, random_access_iterator<int*> >();
    test<const int*, const int*, int*>();

#if TEST_STD_VER > 17
    static_assert(test_constexpr());
#endif

  return 0;
}