1.单链表实现约瑟夫环（JosephCircle）

思路：首先约瑟夫环(约瑟夫问题)是一个数学的应用问题:已知n个人(以编号1，2，3…n分别表示)围坐在一张圆桌周围。从编号为k的人开始报数，数到m的那个人出列;他的下一个人又从1开始报数，数到m的那个人又出列;依此规律重复下去，直到圆桌周围的人全部出列。

 代码如下：

sListNode * JocephCircle(sListNode *pFirst, int k)
{
	assert(pFirst);
	sListNode*pPrev = NULL;
	sListNode *pNode = pFirst;
	int i = 0;
	//将单链表改成循坏链表
	while (pNode->pNext)
	{
		pNode = pNode->pNext;
	}
	pNode->pNext = pFirst;
	//开始执行
	pNode = pFirst;
	while (pNode->pNext!=pNode)
	{
		//找出第k个节点
		for (i = 0; i < k - 1; i++)
		{
			pPrev = pNode;
			pNode = pNode->pNext;
		}
		pPrev->pNext = pNode->pNext;
		free(pNode);
		pNode = pPrev->pNext;
	}
	return pNode;
}

2.求两个已排序单链表中相同的数据

代码如下：

void UnionSet(sListNode *s1, sListNode *s2)
{
	assert(s1);
	assert(s2);
	sListNode *p1 = s1;
	sListNode *p2 = s2;
	while (p1 != NULL&&p2 != NULL)
	{
		if (p1->data <p2->data)
		{
			p1 = p1->pNext;
		}
		else if (p1->data>p2->data)
		{
			p2 = p2->pNext;
		}
		else
		{
			printf("%d ", p1->data);
			p1 = p1->pNext;
			p2 = p2->pNext;
		}
	}
}

3.复制链表。一个链表的每个节点，有一个next指针指向下一个节点，还有一个random指针指向这个链表的一个随机节点或者NULL,复制这个链表，返回复制后的新链表

主要分三步：

• 复制新结点放在老结点后边
• 复制random
• 拆链表

代码如下：

ListNode *ListRandom(ListNode *pFirst)
{
	assert(pFirst);
	ListNode *pNode;
	ListNode *pNewNode;
	ListNode *pOldRandom;
	ListNode *pNewRandom;
	//1.复制结点放在老结点后边
	for (pNode = pFirst; pNode != NULL; pNode = pNode->pNext->pNext){
		pNewNode = (ListNode *)malloc(sizeof(ListNode));
		pNewNode->data = pNode->data;
		pNewNode->pNext = pNode->pNext;
		pNode->pNext = pNewNode;
	}
	//2.复制random
	for (pNode = pFirst; pNode != NULL; pNode = pNode->pNext->pNext){
		pNewNode = pNode->pNext;
		pOldRandom = pNode->random;
		if (pOldRandom != NULL){
			pNewRandom = pOldRandom->pNext;
			pNewNode->random = pNewRandom;
		}
	}
	//3.拆链表
	ListNode *pNewFirst = pFirst -> pNext;
	for (pNode = pFirst; pNode != NULL; pNode = pNode->pNext->pNext){
		pNewNode = pNode->pNext;
		pNode->pNext = pNewNode->pNext;
		if (pNode->pNext != NULL){
			pNewNode->pNext = pNode->pNext->pNext;
		}
		else
		{
			pNewNode->pNext = NULL;
		}
		return pNewNode;
	}
}