public class MergeBU { private static Comparable[] aux; // auxiliary array for merges // See page 271 for merge() code. public static void sort(Comparable[] a) { // Do lg N passes of pairwise merges. int N = a.length; aux = new Comparable[N]; for (int sz = 1; sz < N; sz = sz+sz) // sz: subarray size for (int lo = 0; lo < N-sz; lo += sz+sz) // lo: subarray index merge(a, lo, lo+sz-1, Math.min(lo+sz+sz-1, N-1)); } }