C语言快速排序算法

Linklist Quicksort(Linklist *listHead, Linklist *listTail)
{
	Lnode *current;
	Lnode* lessHead = NULL, *lessTail = NULL, *moreHead = NULL, *moreTail = NULL;
	current = (*listHead)->next;//每次取首节点为枢纽，current指向第二个节点用于遍历
	if ((*listHead)->next != NULL)//当链表节点数不为1时(说明链表未排好序)
	{
		for (current = (*listHead)->next; current; current = current->next)
		{
			if (current->key < (*listHead)->key)
			{
				if (lessHead == NULL)
					lessHead = current;
				else
					lessTail->next = current;
				lessTail = current;
			}//current结点key小于枢纽key时放入less链表
			else
			{
				if (moreHead == NULL)
					moreHead = current;
				else
					moreTail->next = current;
				moreTail = current;
			}//current结点key大于枢纽key时放入more链表
		}
		//根据枢纽结点将T链表分为less和more两个链表
		if (moreTail)
			moreTail->next = NULL;
		if (lessTail)
			lessTail->next = NULL;
		//将more链表尾结点next域置空
		if (moreHead != NULL)
		{
			moreTail->next = NULL;
			Quicksort(&moreHead, &moreTail);
			(*listHead)->next = moreHead;
			*listTail = moreTail;
		}
		//若moreHead不空，则current为more链表的尾结点，对more链表进行递归处理,将more链表接在枢纽节点后
		else
		{
			(*listHead)->next = NULL;
			*listTail = *listHead;
		}
		//若moreHead为空，则只有less链表(即结点key全小于枢纽)，将枢纽结点接在less节点后
		if (lessHead != NULL)
		{
			lessTail->next = NULL;
			Quicksort(&lessHead, &lessTail);
			lessTail->next = *listHead;
			*listHead = lessHead;
		}
		//若lesseHead不空，对less链表进行递归处理，再将枢纽节点接在less链表后
		else
		{
			lessHead = *listHead;
		}
		//若lesseHead为空，则枢纽结点作为首节点
		return lessHead;
	}
	else
		return *listHead;
}

#include<stdio.h>
#include<malloc.h> 
typedef struct Lnode
{
	int key;
	struct Lnode* next;
}Lnode, *Linklist;
//链表结构体类型
Linklist createList(Linklist L, int n)
{
	L = (Linklist)malloc(sizeof(Lnode));
	L->next = NULL;
	Lnode *p, *r;
	r = L;
	p = (Lnode*)malloc(sizeof(Lnode));
	scanf("%d", &r->key);
	for (int i = 1; i < n; i++)
	{
		p = (Lnode*)malloc(sizeof(Lnode));
		scanf("%d", &p->key);
		r->next = p;
		r = p;
	}
	r->next = NULL;
	return L;
}
//初始初始化及尾插法（正序）创建单链表
Linklist getTail(Linklist L)
{
	while (L->next)
		L = L->next;
	return L;
}
//得到尾指针
void Print(Linklist L)
{
	Lnode *p;
	p = L;
	while (p)
	{
		printf("%d ", p->key);
		p = p->next;
	}
}
//遍历单链表
Linklist Quicksort(Linklist *listHead, Linklist *listTail)
{
	Lnode *current;
	Lnode* lessHead = NULL, *lessTail = NULL, *moreHead = NULL, *moreTail = NULL;
	current = (*listHead)->next;//每次取首节点为枢纽，current指向第二个节点用于遍历
	if ((*listHead)->next != NULL)//当链表节点数不为1时(说明链表未排好序)
	{
		for (current = (*listHead)->next; current; current = current->next)
		{
			if (current->key < (*listHead)->key)
			{
				if (lessHead == NULL)
					lessHead = current;
				else
					lessTail->next = current;
				lessTail = current;
			}//current结点key小于枢纽key时放入less链表
			else
			{
				if (moreHead == NULL)
					moreHead = current;
				else
					moreTail->next = current;
				moreTail = current;
			}//current结点key大于枢纽key时放入more链表
		}
		//根据枢纽结点将T链表分为less和more两个链表
		if (moreTail)
			moreTail->next = NULL;
		if (lessTail)
			lessTail->next = NULL;
		//将more链表尾结点next域置空
		if (moreHead != NULL)
		{
			moreTail->next = NULL;
			Quicksort(&moreHead, &moreTail);
			(*listHead)->next = moreHead;
			*listTail = moreTail;
		}
		//若moreHead不空，则current为more链表的尾结点，对more链表进行递归处理,将more链表接在枢纽节点后
		else
		{
			(*listHead)->next = NULL;
			*listTail = *listHead;
		}
		//若moreHead为空，则只有less链表(即结点key全小于枢纽)，将枢纽结点接在less节点后
		if (lessHead != NULL)
		{
			lessTail->next = NULL;
			Quicksort(&lessHead, &lessTail);
			lessTail->next = *listHead;
			*listHead = lessHead;
		}
		//若lesseHead不空，对less链表进行递归处理，再将枢纽节点接在less链表后
		else
		{
			lessHead = *listHead;
		}
		//若lesseHead为空，则枢纽结点作为首节点
		return lessHead;
	}
	else
		return *listHead;
}
int main()
{
	Lnode* L = NULL;
	int n;
	printf("请输入元素个数\n");
	scanf("%d", &n);
	printf("请输入元素\n");
	L = createList(L, n);
	Lnode* listTail;
	listTail = getTail(L);
	Quicksort(&L, &listTail);
	printf("排序后元素序列为\n");
	Print(L);
	return 0;
}