以下是代码，利用Comparable实现，简单直接。
import org.junit.Test;
import java.util.Arrays;
public class Merge {
private static Comparable[] assist;
private static boolean greater(Comparable v,Comparable w){
return v.compareTo(w)<0;
}
public static void sort(Comparable[] a){
assist = new Comparable[a.length];
int lo = 0;
int hi = a.length-1;
sort(a,lo,hi);
}
private static void sort(Comparable[] a,int lo,int hi){
if(hi<=lo){
return;
}
int mid = lo+(hi-lo)/2;
sort(a,lo,mid);
sort(a,mid+1,hi);
merge(a,lo,mid,hi);
}
private static void merge(Comparable[] a,int lo,int mid,int hi){
int i = lo;
int p1 = lo;
int p2 = mid+1;
while (p1<=mid&&p2<=hi){
if(greater(a[p1],a[p2])){
assist[i++] = a[p1++];
}else {
assist[i++] = a[p2++];
}
}
while(p1<=mid){
assist[i++] = a[p1++];
}
while(p2<=hi){
assist[i++] = a[p2++];
}
for (int index = lo; index <=hi; index++) {
a[index] = assist[index];
}
}
@Test
public void TestMerge(){
Comparable[] a = new Comparable[] {9,5,6,7,8,4,3,2,1,0};
System.out.println("待排序数组 "+Arrays.toString(a));
sort(a);
System.out.println(Arrays.toString(a));
}
}
