struct Compare {double val; size_t index;};
#pragma omp declare reduction(minimum : struct Compare : omp_out = omp_in.val < omp_out.val ? omp_in : omp_out)

size_t FindNearestCentroid(const Points& centroids, const Point& point) {
    struct Compare min;
    min.val = Distance(point, centroids[1]);
    min.index = 1;

    #pragma omp parallel for reduction(minimum: min)
    for (size_t i = 1; i < centroids.size(); ++i) {
        double distance = Distance(point, centroids[i]);
        if (distance < min.val) {
            min.val = distance;
            min.index = i;
        }
    }
    return min.index;
}