Optimizada

void solver(vector <int> v1,vector <int> v2)
{
        sort(v1.begin(),v1.end());
        sort(v2.begin(),v2.end());
        int cont1=0,cont2=0;
        int limit1=v1.size(), limit2=v2.size();
        while(cont2!=limit2 and cont1!=limit1)
        {
            if(v1[cont1]!=v2[cont2])
            {
                if(v1[cont1]<v2[cont2])
                    cont1++;
                else
                    cont2++;
            }
            else
            {
                printf("%d\n", v1[cont1++]);
                cont2++;
            }
        }
}