希尔排序——C++实现

希尔排序C++实现

很有意思，有点像归并排序，但是分组的策略不同。希尔排序的分组策略是a[i+k*gap]一组，k=0,1,2…。

template_head.h

#include 
#include "../head_file/template_head.h"
#include 

using namespace std;

void shell_sort()
{
	cout << "Shell Sort!!!" << endl;

	vector<int> sort_list = { 8,9,1,7,2,3,5,4,6,0 };
	shellSort(sort_list.begin(), sort_list.end());
	for (auto x : sort_list) {
		cout << x << " ";
	}
	cout << endl;

}

template <typename Iterator>
void shellSort(const Iterator& begin, const Iterator& end) 
{
	shellSort(begin, end, less_<decltype(*begin)>{});
}

template <typename Iterator, typename Comparator>
void shellSort(const Iterator& begin, const Iterator& end, Comparator lessThan)
{
	if (begin == end)
		return;
	auto size = end - begin;

	for (auto gap = size / 2 ; gap > 0; gap /= 2) {
		for (Iterator i = begin + gap; i != end; i++) {
			auto tmp = std::move(*(i));
			Iterator j;
			for (j = i; j >= begin+gap && lessThan(tmp, *(j - gap)); j -= gap) {
				*j = std::move(*(j - gap));    // 向后移动一个gap
			}
			*j = std::move(tmp);
		}
	}

}