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#include "helpers.h"
#include <algorithm>
#include <iterator>
namespace NErasure {
TPartIndexList MakeSegment(int begin, int end) {
TPartIndexList result(end - begin);
for (int i = begin; i < end; ++i) {
result[i - begin] = i;
}
return result;
}
TPartIndexList MakeSingleton(int elem) {
TPartIndexList result;
result.push_back(elem);
return result;
}
TPartIndexList Difference(int begin, int end, const TPartIndexList& subtrahend) {
size_t pos = 0;
TPartIndexList result;
for (int i = begin; i < end; ++i) {
while (pos < subtrahend.size() && subtrahend[pos] < i) {
pos += 1;
}
if (pos == subtrahend.size() || subtrahend[pos] != i) {
result.push_back(i);
}
}
return result;
}
TPartIndexList Difference(const TPartIndexList& first, const TPartIndexList& second) {
TPartIndexList result;
std::set_difference(first.begin(), first.end(), second.begin(), second.end(), std::back_inserter(result));
return result;
}
TPartIndexList Difference(const TPartIndexList& set, int subtrahend) {
return Difference(set, MakeSingleton(subtrahend));
}
TPartIndexList Intersection(const TPartIndexList& first, const TPartIndexList& second) {
TPartIndexList result;
std::set_intersection(first.begin(), first.end(), second.begin(), second.end(), std::back_inserter(result));
return result;
}
TPartIndexList Union(const TPartIndexList& first, const TPartIndexList& second) {
TPartIndexList result;
std::set_union(first.begin(), first.end(), second.begin(), second.end(), std::back_inserter(result));
return result;
}
bool Contains(const TPartIndexList& set, int elem) {
return std::binary_search(set.begin(), set.end(), elem);
}
TPartIndexList UniqueSortedIndices(const TPartIndexList& indices) {
TPartIndexList copy = indices;
std::sort(copy.begin(), copy.end());
copy.erase(std::unique(copy.begin(), copy.end()), copy.end());
return copy;
}
TPartIndexList ExtractRows(const TPartIndexList& matrix, int width, const TPartIndexList& rows) {
Y_ASSERT(matrix.size() % width == 0);
TPartIndexList result(width * rows.size());
for (size_t i = 0; i < rows.size(); ++i) {
auto start = matrix.begin() + rows[i] * width;
std::copy(start, start + width, result.begin() + i * width);
}
return result;
}
} // namespace NErasure
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