希尔排序

#include <stdio.h>

int main()
{
const int n = 5;
int i, j, temp;
int gap = 0;
int a[] = {5, 4, 3, 2, 1};
while (gap<=n)
{
gap = gap * 3 + 1;
}
while (gap > 0)
{
for ( i = gap; i < n; i++ )
{
j = i - gap;
temp = a[i];
while (( j >= 0 ) && ( a[j] > temp ))
{
a[j + gap] = a[j];
j = j - gap;
}
a[j + gap] = temp;
}
gap = ( gap - 1 ) / 3;
}
}

void shellsort(int *data, size_t size)
{
for (int gap = size / 2; gap > 0; gap /= 2)
for (int i = gap; i < size; ++i)
{

int key = data[i];
int j = 0;
for( j = i -gap; j >= 0 && data[j] > key; j -=gap)
{
data[j+gap] = data[j];
}
data[j+gap] = key;
}
}

static <E extends Comparable<? super E>> void shellSort(List<E> a) {
int h = 1;
while (h < a.size()/3) h = h*3 + 1;    // <O(n^(3/2)) by Knuth,1973>: 1, 4, 13, 40, 121, ...
for (; h >= 1; h /= 3)
for (int i = h; i < a.size(); i++)
for (int j = i; j >= h && a.get(j).compareTo(a.get(j-h)) < 0; j-=h)
Collections.swap(a, j, j-h);
}