希尔排序

//希尔排序（分组式的直接插入排序）
void shell_group_pass(int* buf, int len, int increment) {

 printf("shell group pass %d\n", increment);
 for(int i=0; i  for(int j=i+increment; j   int now = buf[j];
   if(now > buf[j-increment])continue;
   int k;
   for(k=j-increment; k>=0; k-=increment) {
    if(buf[k] > now)buf[k+increment] = buf[k];
    else break;
   }
   buf[k+increment] = now;
  }
 }
}
void shell_sort(int* buf, int len) {

 int increment = 12;
 do {
  increment = increment/3+1;
  shell_group_pass(buf, len, increment);
 } while(increment > 1);
 
}