// 希爾排序（Shell Sort）
void ShellSort(SqList *L)
{
    int i, j;
    int increment = L->length;  // 先讓增量初始化為序列的長度
    do {
        increment = increment / 3 + 1;   // 計算增量的值
        for (i = increment + 1; i <= L->length; i ++ ) { 
            if (L->arr[i] < L->arr[i - increment]) {   // 如果L->[i]需要插入有序增量子表
                L->arr[0] = L->arr[i];   // 暫存在哨兵位
                for (j = i - increment; j > 0 && L->arr[0] < L->arr[j]; j -= increment) {  // 遍歷增量子表，尋找插入位置
                    L->arr[j + increment] = L->arr[j];
                }
                L->arr[j+increment] = L->arr[0];  // 插入
            }
        }
    } while (increment > 1);
}

#include <iostream>
using namespace std;

const int N = 100;

typedef struct
{
    int arr[N];    // 存儲待排序的序列
    int length;    // 存儲序列的長度
} SqList;

void ShellSort(SqList *L)
{
    int i, j;
    int increment = L->length;
    do {
        increment = increment / 3 + 1;
        for (i = increment + 1; i <= L->length; i ++ ) {
            if (L->arr[i] < L->arr[i - increment]) {
                L->arr[0] = L->arr[i];
                for (j = i - increment; j > 0 && L->arr[0] < L->arr[j]; j -= increment)
                    L->arr[j + increment] = L->arr[j];
                L->arr[j + increment] = L->arr[0];
            }
        }
    } while (increment > 1);
}

int main()
{
    SqList L;
    L.arr[1] = 50;
    L.arr[2] = 10;
    L.arr[3] = 90;
    L.arr[4] = 30;
    L.arr[5] = 70;
    L.arr[6] = 40;
    L.arr[7] = 80;
    L.arr[8] = 60;
    L.arr[9] = 20;
    L.length = 9;

    ShellSort(&L);
    for (int i = 1; i <= L.length; i ++ )
        cout << L.arr[i] << " ";

}