static int Triangle(int[] a)
{
    var sorted = (int[])a.Clone();
    Array.Sort(sorted);
    var c = sorted.Length;
    if (c < 3)
    {
        return 0;
    }

    for (int i = 0; i < c - 2; i++)
    {
        if (sorted[i] > 0 && sorted[i] > (long)sorted[i + 2] - sorted[i + 1])
        {
            return 1;
        }
    }

    return 0;
}