求交集法

#include <algorithm>
#include <iostream>
#include <vector>
#include <iterator>
 
int main() {
    std::vector<int> v1;
    std::vector<int> v2;
    int n,m;
    std::cin>>n>>m;
    while(n--){
        int obj;
        std::cin>>obj;
        v1.push_back(obj);
    }while(m--){
        int obj;
        std::cin>>obj;
        v2.push_back(obj);
    }
    std::vector<int> intersection;
    std::sort(v1.begin(),  v1.end()); 
    std::sort(v2.begin(),  v2.end()); 
    std::set_intersection(
        v1.begin(),  v1.end(), 
        v2.begin(),  v2.end(), 
        std::back_inserter(intersection)
    );
    for (int num : intersection) {
        std::cout << num << " ";
    }
    return 0;
}