3.3

#include <iostream>
#include <vector>
#include <set>
#include <random>
#include <ctime>
using namespace std;

int main() {
    default_random_engine rnd(time(0));
    uniform_int_distribution<unsigned> g(10, 50);
    vector<int> myVektor;
    int n, k = 0;
    cout << "n = "; cin >> n;
    for (int i = 0; i < n; i  ) {
        int d = g(rnd);
        myVektor.push_back(d);
        cout << myVektor[i] << " ";
    }
    set<int> mySet;
    for (int i = 1; i <= 5;   i) mySet.insert(i * 10);
    cout << endl;
    for (int i = 0; i < n; i  )
        if (mySet.count(myVektor[i])) k  ;
    cout << k << "  ta element topildi." << endl;
    system("pause");
    return 0;
}
Run on cpp.sh