static int maxDifference(int[] a)
{
	int high = a[0];
	int low = a[0];
	int diff = -1;

	for (int i = 1; i < a.Length; i++)
	{
		int current = a[i];

		if (current > high)
		{
			high = current;
			diff = high - low;
			continue;
		}

		if (current < low)
		{
			low = current;
			high = diff > 0 ? low + diff : low;
		}
	}

	return diff;
}