#include <iostream>
#include <iterator>
#include <vector>
#include <set>
#include <algorithm>
 
int main() {
    std::vector<int> a = {1,2,3,4,5,5};
    std::vector<int> b = {5,5,5,5,4};
    std::vector<int> c;
 
    std::set<int> a1(a.begin(), a.end());
    std::set<int> b1(b.begin(), b.end());
 
    std::set_intersection(a1.begin(), a1.end(), b1.begin(), b1.end(), std::back_inserter(c));
 
    for (auto &x : c) {
        std::cout << x << std::endl;
    }
}

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