2.1.12令希爾排序打印出遞增序列的每個元素所帶來的比較次數和數組大小的比值。編寫一個測試用例對隨機Double數組進行希爾排序，驗證該值是一個小常數，數組大小按照10的冪次遞增，不小於100。


public class E2d1d12
{
public static int compareTimes=0;
public static int maxRate=0;
public static void sort(Comparable[] a)
{
int N=a.length;
int h=1;
while (h<N/3) h=3*h+1;
while (h>=1)
{
compareTimes=0;
for (int i=h;i<N;i++)
{
for (int j=i;j>=h && less(a[j],a[j-h]);j-=h)
exch(a,j,j-h);

}
if(compareTimes/N>maxRate) maxRate= compareTimes/N;
StdOut.printf("N=%d,h=%d,compareTimes=%d,rate=%d\n",N,h,compareTimes,compareTimes/N);
h=h/3;
}
}

private static boolean less(Comparable v,Comparable w)
{
compareTimes++;
return v.compareTo(w)<0;
}

private static void exch(Comparable[] a,int i,int j)
{
Comparable t=a[i];
a[i]=a[j];
a[j]=t;
}

private static void show(Comparable[] a)
{
for (int i=0;i<a.length;i++)
StdOut.print(a[i]+" ");
StdOut.println();
}

public static boolean isSorted(Comparable[] a)
{
for (int i=0;i<a.length;i++)
if(less(a[i],a[i-1])) return false;
return true;
}

public static void main(String[] args)
{

for ( int N=100;N<=10000000;N=N*10)
{
Double[] a=new Double[N];
for (int i=0;i<N;i++)
a[i]=StdRandom.uniform(100.0,100000000.0);
sort(a);
}
StdOut.println("maxRate=" + maxRate);
}

}

Algs4-2.1.12令希爾排序打印出遞增序列的每個元素所帶來的比較次數和數組大小的比值