//===----------------------------------------------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

// <algorithm>

// template<BidirectionalIterator Iter, StrictWeakOrder<auto, Iter::value_type> Compare>
//   requires ShuffleIterator<Iter>
//         && CopyConstructible<Compare>
//   void
//   inplace_merge(Iter first, Iter middle, Iter last, Compare comp);

#include <algorithm>
#include <functional>
#include <cassert>
#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
#include <memory>

struct indirect_less
{
    template <class P>
    bool operator()(const P& x, const P& y)
        {return *x < *y;}
};

#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES

#include "test_iterators.h"

template <class Iter>
void
test_one(unsigned N, unsigned M)
{
    assert(M <= N);
    int* ia = new int[N];
    for (unsigned i = 0; i < N; ++i)
        ia[i] = i;
    std::random_shuffle(ia, ia+N);
    std::sort(ia, ia+M, std::greater<int>());
    std::sort(ia+M, ia+N, std::greater<int>());
    std::inplace_merge(Iter(ia), Iter(ia+M), Iter(ia+N), std::greater<int>());
    if(N > 0)
    {
        assert(ia[0] == N-1);
        assert(ia[N-1] == 0);
        assert(std::is_sorted(ia, ia+N, std::greater<int>()));
    }
    delete [] ia;
}

template <class Iter>
void
test(unsigned N)
{
    test_one<Iter>(N, 0);
    test_one<Iter>(N, N/4);
    test_one<Iter>(N, N/2);
    test_one<Iter>(N, 3*N/4);
    test_one<Iter>(N, N);
}

template <class Iter>
void
test()
{
    test_one<Iter>(0, 0);
    test_one<Iter>(1, 0);
    test_one<Iter>(1, 1);
    test_one<Iter>(2, 0);
    test_one<Iter>(2, 1);
    test_one<Iter>(2, 2);
    test_one<Iter>(3, 0);
    test_one<Iter>(3, 1);
    test_one<Iter>(3, 2);
    test_one<Iter>(3, 3);
    test<Iter>(4);
    test<Iter>(100);
    test<Iter>(1000);
}

int main()
{
    test<bidirectional_iterator<int*> >();
    test<random_access_iterator<int*> >();
    test<int*>();

#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
    {
    unsigned N = 100;
    unsigned M = 50;
    std::unique_ptr<int>* ia = new std::unique_ptr<int>[N];
    for (unsigned i = 0; i < N; ++i)
        ia[i].reset(new int(i));
    std::random_shuffle(ia, ia+N);
    std::sort(ia, ia+M, indirect_less());
    std::sort(ia+M, ia+N, indirect_less());
    std::inplace_merge(ia, ia+M, ia+N, indirect_less());
    if(N > 0)
    {
        assert(*ia[0] == 0);
        assert(*ia[N-1] == N-1);
        assert(std::is_sorted(ia, ia+N, indirect_less()));
    }
    delete [] ia;
    }
#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
}