《算法导论》归并排序----merge-sort

public class MergeSort {

public static void sort(double [] A,int p, int r)
{
if(p<r)
{
int q = (int) Math.floor( (p+r)/2 );
sort(A,p,q);
sort(A,q+1,r);
merge(A,p,q,r);
}
return ;

}
public static void merge(double [] A, int p, int q, int r)
{
int n1 = q-p+1;
int n2 = r-q;
double [] L = new double[n1];
double [] R = new double[n2];
for(int i=0; i<n1; i++)
L[i] = A[p+i];
for(int i=0; i<n2;i++)
R[i]=A[q+i+1];

int i=0;
int j=0;
int counter = p;
while(i<L.length && j<R.length)
{
if(L[i]<=R[j])
{
A[counter]=L[i];
i++;
}
else
{
A[counter]=R[j];
j++;
}
counter++;
}
if(i==L.length)
{
for(int k=j;k<R.length;k++)
A[counter++] = R[k];
}
else
{
for(int k=i;k<L.length;k++)
A[counter++] = L[k];
}
}
public static void main(String[] args) {
// TODO Auto-generated method stub
double [] A = {1.3, 5 ,2, 6.9, 2.0,7.8,4.3};
MergeSort.sort(A,0,A.length-1);
for(double a:A)
System.out.print(a+" ");
}
}