希尔排序

原文链接：http://blog.youkuaiyun.com/morewindows/article/details/6668714
简单

void ShellSort(int *a,int n){
    int i,j,k;
    int temp;
    int gap;

    for(gap = n / 2;gap > 0;gap /= 2)
        for(i = 0;i < gap;i++)
            for(j = i + gap;j < n;j += gap)
                if(a[j - gap] > a[j])
                    {
                        temp = a[j];
                        for(k = j - gap;k >= 0 && a[k] > temp; k -= gap)
                        a[k + gap] = a[k];
                        a[k+ gap] = temp;
                    }

}

进阶

void ShellSort2(int *a,int n){
    int i,j,k;
    int gap;

    for(gap = n / 2;gap > 0;gap /= 2)
        for(i = 0;i < gap;i++)
            for(j = i + gap;j < n;j += gap)
                for(k = j - gap;k >= 0 && a[k + gap] > a[k];k -= gap)
                    a[k + gap] = a[k];
}