// http://tinodidriksen.com/2010/01/31/snippet-sort-unique-vector/
#include <vector>
#include <iostream>
#include <algorithm>

int main() {
    std::vector<int> vec1;
    vec1.push_back(1);
    vec1.push_back(2);
    vec1.push_back(3);
    vec1.push_back(1);
    vec1.push_back(2);
    vec1.push_back(3);
    vec1.push_back(1);

    std::sort(vec1.begin(), vec1.end());
    vec1.erase(std::unique(vec1.begin(), vec1.end()), vec1.end());

    std::cout << vec1.size() << std::endl;
    std::cout << vec1[0] << vec1[1] << vec1[2] << std::endl;
}