#include <iostream>
#include <string>
#include <algorithm>
#include <set>
#include <iterator>
 
std::set<std::string> palindromeGen(std::string charactersSet) 
{
    std::set<std::string> pals;
    std::sort(charactersSet.begin(), charactersSet.end());
    do
    {
    	if ( std::string(charactersSet.rbegin(), charactersSet.rend()) == charactersSet )
    	   pals.insert(charactersSet);
    } while (std::next_permutation(charactersSet.begin(), charactersSet.end()));
    return pals;
}
 
int main()
{ 
	auto retVal = palindromeGen("abcabc");
	std::cout << retVal.size() << '\n';
	std::copy(retVal.begin(), retVal.end(), std::ostream_iterator<std::string>(std::cout, "\n"));
}

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