Hill (shell) sort __ Hill Shell sort

The average time complexity of hill sort is O (nlog2n), Space complexity is O (1), time performance between O (n^2) and O (nlog2n). Hill sort is an unstable sort method whose performance can be fully played in the number of records to be sorted.

The basic idea of hill sorting: First, the whole sequence of sorted records is divided into several sub sequences, in the subsequence, the direct insertion sort is carried out, while the whole sequence is in order, then the whole record is inserted into the sequence directly, because in the direct insertion sort, the key word in the sorted record is very efficient.

Hill sort needs to solve two problems: first, how to split with the sorting record; second, how to sort the direct access in the subsequence. The following code is detailed.

Hill sort
#include <iostream>
using namespace std;
void Shellsort (int a[],int n) {
	int gap;
	for (gap=n/2;gap>0;gap/=2) {    //calculate each step for
		(int i=gap;i<n;i++) {   //start from the element of Gap, Each element is directly inserted into a sort
			if (A[i]<a[i-gap]) {
				int temp=a[i] with the data within its own group;
				for (int j=i-gap; (j>=0) && (Temp<a[j]); j-=gap) a[j+gap]=a[j];
				A[j+gap]=temp
			}
		}
		cout<< "before sort:";
		for (int k=0;k<10;k++)
			cout<<a[k]<< "";
		cout<<endl;
	}
}
void Main () {
	int a[10]={2,6,1,10,9,3,0,100,-1,7};
	Shellsort (a,10);
	cout<< "after sort:";
	for (int i=0;i<10;i++)
		cout<<a[i]<< "";
	cout<<endl;
}

The results of the operation are as follows: