希尔排序

//希尔排序
class ShellSort{
    public void sort(int[] a){
        int d,i,j,temp;
        for ( d = a.length/2; d >= 1; d=d/2) {
            for ( i = d; i <a.length ; i=i+d) {
                if (a[i]<a[i-d]){
                    temp = a[i];
                    for ( j = i-d; j>=0 && a[j] >temp ; j= j-d) {
                        a[j+d] = a[j];
                    }
                    a[j+d] = temp;
                }
            }
        }
    }
}

//哨兵版
class ShellSort{
    public void sort(int[] a){
        int d,i,j;
        for ( d = (a.length-1)/2; d >= 1; d=d/2) {
            for ( i = d+1; i <=a.length-1 ; i=i+d) {
                if (a[i]<a[i-d]){
                    a[0] = a[i];
                    for ( j = i-d; j>0 && a[j] >a[0] ; j= j-d) {
                        a[j+d] = a[j];
                    }
                    a[j+d] = a[0];
                }
            }
        }
    }
}