|
|
#ifndef SCIQLOP_SORTUTILS_H
|
|
|
#define SCIQLOP_SORTUTILS_H
|
|
|
|
|
|
#include <algorithm>
|
|
|
#include <numeric>
|
|
|
#include <vector>
|
|
|
|
|
|
/**
|
|
|
* Utility class with methods for sorting data
|
|
|
*/
|
|
|
struct SortUtils {
|
|
|
/**
|
|
|
* Generates a vector representing the index of insertion of each data of a container if this
|
|
|
* one had to be sorted according to a comparison function.
|
|
|
*
|
|
|
* For example:
|
|
|
* If the container is a vector {1; 4; 2; 5; 3} and the comparison function is std::less, the
|
|
|
* result would be : {0; 3; 1; 4; 2}
|
|
|
*
|
|
|
* @tparam Container the type of the container.
|
|
|
* @tparam Compare the type of the comparison function
|
|
|
* @param container the container from which to generate the result. The container must have a
|
|
|
* at() method that returns a value associated to an index
|
|
|
* @param compare the comparison function
|
|
|
*/
|
|
|
template <typename Container, typename Compare>
|
|
|
static std::vector<int> sortPermutation(const Container &container, const Compare &compare)
|
|
|
{
|
|
|
auto permutation = std::vector<int>{};
|
|
|
permutation.resize(container.size());
|
|
|
|
|
|
std::iota(permutation.begin(), permutation.end(), 0);
|
|
|
std::sort(permutation.begin(), permutation.end(),
|
|
|
[&](int i, int j) { return compare(container.at(i), container.at(j)); });
|
|
|
return permutation;
|
|
|
}
|
|
|
|
|
|
/**
|
|
|
* Sorts a container according to indices passed in parameter
|
|
|
* @param container the container sorted
|
|
|
* @param sortPermutation the indices used to sort the container
|
|
|
* @return the container sorted
|
|
|
* @warning no verification is made on validity of sortPermutation (i.e. the vector has unique
|
|
|
* indices and its range is [0 ; vector.size()[ )
|
|
|
*/
|
|
|
template <typename Container>
|
|
|
static Container sort(const Container &container, const std::vector<int> &sortPermutation)
|
|
|
{
|
|
|
if (container.size() != sortPermutation.size()) {
|
|
|
return Container{};
|
|
|
}
|
|
|
|
|
|
// Inits result
|
|
|
auto sortedData = Container{};
|
|
|
sortedData.resize(container.size());
|
|
|
|
|
|
std::transform(sortPermutation.cbegin(), sortPermutation.cend(), sortedData.begin(),
|
|
|
[&container](int i) { return container.at(i); });
|
|
|
|
|
|
return sortedData;
|
|
|
}
|
|
|
};
|
|
|
|
|
|
#endif // SCIQLOP_SORTUTILS_H
|
|
|
|