int minimumDistances(vector<int> a) {
    vector<int> distance;
    for (int i = 0; i < a.size(); i++) {
        for (int j = i + 1; j < a.size(); j++){
            if (a[i] == a[j]) {
                distance.push_back(j - i);
            }
        }
    }
    sort(distance.begin(), distance.end());
    return (distance.size() > 0) ? distance[0] : -1;
}