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//===----------------------------------------------------------------------===//
//
//                     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.
//
//===----------------------------------------------------------------------===//

// <numeric>
// UNSUPPORTED: c++98, c++03, c++11, c++14

// template<class InputIterator, class OutputIterator, class T>
//     OutputIterator exclusive_scan(InputIterator first, InputIterator last,
//                                   OutputIterator result, T init);
// 

#include <numeric>
#include <vector>
#include <cassert>

#include "test_iterators.h"

template <class Iter1, class T, class Iter2>
void
test(Iter1 first, Iter1 last, T init, Iter2 rFirst, Iter2 rLast)
{
    std::vector<typename std::iterator_traits<Iter1>::value_type> v;
    
//  Not in place
    std::exclusive_scan(first, last, std::back_inserter(v), init);
    assert(std::equal(v.begin(), v.end(), rFirst, rLast));

//  In place
    v.clear();
    v.assign(first, last);
    std::exclusive_scan(v.begin(), v.end(), v.begin(), init);
    assert(std::equal(v.begin(), v.end(), rFirst, rLast));  
}


template <class Iter>
void
test()
{
          int ia[]   = {1, 3, 5, 7,  9};
    const int pRes[] = {0, 1, 4, 9, 16};
    const unsigned sa = sizeof(ia) / sizeof(ia[0]);
    static_assert(sa == sizeof(pRes) / sizeof(pRes[0]));       // just to be sure

    for (unsigned int i = 0; i < sa; ++i )
        test(Iter(ia), Iter(ia + i), 0, pRes, pRes + i);
}

int triangle(int n) { return n*(n+1)/2; }

//  Basic sanity
void basic_tests()
{
    {
    std::vector<int> v(10);
    std::fill(v.begin(), v.end(), 3);
    std::exclusive_scan(v.begin(), v.end(), v.begin(), 50);
    for (size_t i = 0; i < v.size(); ++i)
        assert(v[i] == 50 + (int) i * 3);
    }

    {
    std::vector<int> v(10);
    std::iota(v.begin(), v.end(), 0);
    std::exclusive_scan(v.begin(), v.end(), v.begin(), 30);
    for (size_t i = 0; i < v.size(); ++i)
        assert(v[i] == 30 + triangle(i-1));
    }

    {
    std::vector<int> v(10);
    std::iota(v.begin(), v.end(), 1);
    std::exclusive_scan(v.begin(), v.end(), v.begin(), 40);
    for (size_t i = 0; i < v.size(); ++i)
        assert(v[i] == 40 + triangle(i));
    }

}

int main()
{
    basic_tests();

//  All the iterator categories
    test<input_iterator        <const int*> >();
    test<forward_iterator      <const int*> >();
    test<bidirectional_iterator<const int*> >();
    test<random_access_iterator<const int*> >();
    test<const int*>();
    test<      int*>();
}