sort reproducer

#include <iostream>
#include <numeric>
#include <vector>
#include <algorithm>

int main() {
    std::vector<int64_t> result(10);
    std::iota(result.begin(), result.end(), 0);
    auto start = std::next(result.begin(), 1);
    auto stop = std::next(result.begin(), 4);
    const int64_t fromptr[10] = {100, 300, 200, 400, 500, 600, 700, 800, 1000, 900};
    std::stable_sort(start, stop, [&fromptr](int64_t i1, int64_t i2) {
        return fromptr[i1] < fromptr[i2];
      });
    //std::transform(start, stop, start, [&](int64_t j) -> int64_t {
    //  return j - 3;
    //});
    for(int i=0; i < 10; i++)
      std::cout << result[i] << ' ';
    std::cout << "\n";
    return 0;
}