希尔排序

#include <cstdio>

int main() {
    void ShellSort(int *a, int len);
    const int MAXLEN = 10;
    int a[MAXLEN] = {3, 8, 9, 1, 0, 2, 5, 7, 4, 6};

    printf("befor sort:");
    for(int i=0; i<MAXLEN; ++i) {
        printf("%d ", a[i]);
    }
    putchar('\n');

    ShellSort(a, MAXLEN);

    printf("after sort:");
    for(int i=0; i<MAXLEN; ++i) {
        printf("%d ", a[i]);
    }
    putchar('\n');

    return 0;
}

void ShellSort(int *a, int len) {
    for (int d=len>>1; d>=1; d>>=1) {
        for (int i=d; i<len; ++i) {
            int k = i;
            int tmp = a[i];
            for (int j=i-d; j>=0 && a[j] > tmp; j-=d)  {
                a[j+d] = a[j];
                k = j;
            }
            a[k] = tmp;
        }
    }
}