85 lines
2.4 KiB
C++
85 lines
2.4 KiB
C++
#include "PmergeMe.hpp"
|
|
|
|
template <typename Container>
|
|
Container PmergeMe::sort(Container &data, int level)
|
|
{
|
|
// #1 Create pairs and sort them
|
|
if (data.size() <= 1)
|
|
return data;
|
|
|
|
size_t group_size = 1 << level;
|
|
|
|
int odd = data.size() % (2 * group_size);
|
|
|
|
Container straggler = Container(data.end() - odd, data.end());
|
|
|
|
data.erase(data.end() - odd, data.end());
|
|
|
|
for (size_t i = 0; i < data.size(); i += (2 * group_size))
|
|
{
|
|
if (!less(data[i + group_size - 1], data[i + 2 * group_size - 1]))
|
|
std::swap_ranges(
|
|
data.begin() + i, data.begin() + i + group_size,
|
|
data.begin() + i + group_size);
|
|
}
|
|
|
|
if (2 * group_size < data.size())
|
|
data = sort(data, level + 1);
|
|
|
|
Container main;
|
|
Container pend;
|
|
|
|
// #3 Separate main and pend
|
|
main.insert(main.end(), data.begin(), data.begin() + group_size); // inserting b1
|
|
auto it = data.begin() + group_size; // this is a1
|
|
while (it != data.end())
|
|
{
|
|
main.insert(main.end(), it, it + group_size);
|
|
it += group_size;
|
|
if (it == data.end())
|
|
break;
|
|
pend.insert(pend.end(), it, it + group_size);
|
|
it += group_size;
|
|
}
|
|
pend.insert(pend.end(), straggler.begin(), straggler.end());
|
|
|
|
int i = 0;
|
|
while (!pend.empty())
|
|
{
|
|
int search_window = std::min((1 << (i + 2)) - 1, static_cast<int>(main.size() / group_size));
|
|
|
|
int jacob_index = Jacobstahl().get(i + 3) - Jacobstahl().get(i + 2) - 1;
|
|
int first_to_insert = std::min(jacob_index, static_cast<int>(pend.size() / group_size) - 1);
|
|
|
|
for (int to_insert = first_to_insert; to_insert >= 0; --to_insert)
|
|
insert(main, pend, to_insert, search_window, group_size);
|
|
|
|
i++;
|
|
}
|
|
return main;
|
|
}
|
|
|
|
template <typename Container>
|
|
void PmergeMe::insert(Container &main, Container &pend, int to_insert, int right, int group_size)
|
|
{
|
|
if (pend.empty() || to_insert < 0 || to_insert >= static_cast<int>(pend.size()))
|
|
return;
|
|
|
|
int value_to_insert = pend[(to_insert + 1) * group_size - 1];
|
|
auto insert_pos = main.begin() + right * group_size;
|
|
|
|
int left = 0;
|
|
while (left < right)
|
|
{
|
|
int mid = left + (right - left) / 2;
|
|
int last_idx = std::min((mid + 1) * group_size, static_cast<int>(main.size())) - 1;
|
|
if (less(main[last_idx], value_to_insert))
|
|
left = mid + 1;
|
|
else
|
|
right = mid;
|
|
}
|
|
insert_pos = main.begin() + (left * group_size);
|
|
|
|
main.insert(insert_pos, pend.begin() + to_insert * group_size, pend.begin() + (to_insert + 1) * group_size);
|
|
pend.erase(pend.begin() + to_insert * group_size, pend.begin() + (to_insert + 1) * group_size);
|
|
} |