public static void sort(Comparable[] a, int lo, int hi)
	{
		if (hi <= lo)
			return;
		int j = partition(a, lo, hi); // Partition (see page 291).
		sort(a, lo, j - 1); // Sort left part a[lo .. j-1].
		sort(a, j + 1, hi); // Sort right part a[j+1 .. hi].
	}