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#pragma once
#if defined __GLIBCXX__ && defined _GLIBCXX_DEBUG
#include <utility>
#include <iterator>
// regular STL implementation stripped of debug code
namespace floormat::Heap {
template<typename It, typename Compare>
inline void _push_heap(It first,
std::iter_difference_t<It> holeIndex,
std::iter_difference_t<It> topIndex,
std::iter_value_t<It> value,
Compare& comp)
{
std::iter_difference_t<It> parent = (holeIndex - 1) / 2;
while (holeIndex > topIndex && comp(*(first + parent), value))
{
*(first + holeIndex) = move(*(first + parent));
holeIndex = parent;
parent = (holeIndex - 1) / 2;
}
*(first + holeIndex) = move(value);
}
template<typename It, typename Compare>
void push_heap(It first, It last, Compare comp)
{
_push_heap(first,
std::iter_difference_t<It>((last - first) - 1),
std::iter_difference_t<It>(0),
move(*(last - 1)),
comp);
}
template<typename It, typename Compare>
void _adjust_heap(It first,
std::iter_difference_t<It> holeIndex,
std::iter_difference_t<It> len,
std::iter_value_t<It> value,
Compare& comp)
{
const auto topIndex = holeIndex;
auto secondChild = holeIndex;
while (secondChild < (len - 1) / 2)
{
secondChild = 2 * (secondChild + 1);
if (comp(*(first + secondChild), *(first + (secondChild - 1))))
secondChild--;
*(first + holeIndex) = move(*(first + secondChild));
holeIndex = secondChild;
}
if ((len & 1) == 0 && secondChild == (len - 2) / 2)
{
secondChild = 2 * (secondChild + 1);
*(first + holeIndex) = move(*(first + (secondChild - 1)));
holeIndex = secondChild - 1;
}
_push_heap(first, holeIndex, topIndex, move(value), comp);
}
template<typename It, typename Compare>
void pop_heap(It first, It last, Compare comp)
{
if (last - first > 1)
{
--last;
auto value = move(*last);
*last = move(*first);
_adjust_heap(first,
std::iter_difference_t<It>(0),
std::iter_difference_t<It>(last - first),
move(value),
comp);
}
}
} // namespace floormat::Heap
#else
#include <algorithm>
namespace floormat::Heap {
using std::push_heap;
using std::pop_heap;
} // namespace floormat::Heap
#endif
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