firstUnique

#include<vector>
#include<map>

int solution(vector<int> &A) {
    // write your code in C++14 (g++ 6.2.0)
    using namespace std;

    vector<int> Vaux;
    map<int, int> M;
    int result=-1;


    for (int it : A){
        if (M.count(it)!=0) M[it]+=1;
        else if (M.count(it)==0) {
            M[it]=1;
            Vaux.push_back(it);
        }
    }

    for (int it : Vaux){
        if (M[it]==1) {
            result=it;
            break;
        }

    }

    return result;

}