#include <cstdlib>
#include <iostream>
#include <boost/container/flat_set.hpp>

using namespace std;

int main(int argc, char *argv[])
{
    double d[2] = {0.2, 0.8};
    boost::container::flat_set<double> set;

    set.insert(0);
    set.insert(set.end(), 1);
    set.insert(boost::container::ordered_unique_range_t(), d, d + 2);
    for (double i : set)
        cout << i << endl;

    return EXIT_SUCCESS;
}