07. Sets of Elements

#include <iostream>
#include <string>
#include <set>
#include <vector>
#include <algorithm>

using namespace std;

int main() {
    int n, m, number;
    cin >> n >> m;

    set<int> numbers1;
    set<int> numbers2;

    for (int i = 0; i < n + m; i++) {
        cin >> number;
        i < n ? numbers1.insert(number) : numbers2.insert(number);
    }

    vector<int> numbers3;
    set_intersection(numbers1.begin(), numbers1.end(), numbers2.begin(), numbers2.end(), back_inserter(numbers3));

    for (auto& n : numbers3) {
        cout << n << ' ';
    }

    cout << endl;
    return 0;
}