双向链表的一个C++实现
下面是双向链表的一个C++实现，参考了《数据结构与算法分析C语言版》及不少牛人的分析总结，在此一并感谢了。在VC2005上经反复验证试验，结果非常不错，操作集合以后会继续增加。但可能还有不少bug，如果发现bug, 请告诉我一下。
注意：单链表及双向及循环链表均不使用表头（即哑节点，dummy node）, 即m_pNodeHead指向链表的第一个真正的节点。
/*dlist.h*/
#include
#include
template
class Node
{
public:
T data;
Node *prior;
Node *next;
Node() : data(T()), prior(NULL), next(NULL) {}
Node(const T &initdata) : data(initdata), prior(NULL), next(NULL) {}
};
template
class DList
{
protected:
int m_nCount;
Node *m_pNodeHead;
Node *m_pNodeTail;
public:
DList();
DList(const T &initdata);
DList(const DList& other);
DList& operator=(const DList& other);
~DList();
public:
////插入或删除需要注意处理：插入节点本身的next 和prior,前一个节点的next,后一个节点的prior.
//注意在第一个节点或最后一个节点插入或删除时的特殊情况：前一个或后一个节点为NULL,而且注意移动m_pNodeHead或m_pNodeTail
void Invert();
int IsEmpty() const;
int GetCount() const;
int InsertBefore(const int pos, const T data);
int InsertAfter(const int pos, const T data);
int AddHead(const T data);
int AddTail(const T data);
void RemoveAt(const int pos);
void RemoveHead();
void RemoveTail();
void RemoveAll();
T& GetTail();
T GetTail() const;
T& GetHead();
T GetHead() const;
T& GetAt(const int pos);
T GetAt(const int pos) const;
void SetAt(const int pos, T data);
int Find(const T data) const;
int FindCircle() const;
int FindCross(DList& testlist);
T& GetPrev(int &pos);
T& GetNext(int &pos);
};
template
inline DList::DList() : m_nCount(0), m_pNodeHead(NULL), m_pNodeTail(NULL)
{
}
template
inline DList::DList(const T &initdata)
: m_nCount(0), m_pNodeHead(NULL), m_pNodeTail(NULL)
{
AddHead(initdata);
}
template
inline DList::DList(const DList& other)
: m_nCount(0), m_pNodeHead(NULL), m_pNodeTail(NULL)
{
if(other.m_nCount>0)
{
for(int i=1;i<=other.m_nCount;i++)
{
AddTail(other.GetAt(i));
}
}
}
template
inline DList& DList::operator=(const DList& other)
{
if(this==&other)
{
return *this;
}
if(m_nCount>0)
{
RemoveAll();
}
if(other.m_nCount>0)
{
for(int i=1;i<=other.m_nCount;i++)
{
AddTail(other.GetAt(i));
}
}
return *this;
}
template
inline DList::~DList()
{
RemoveAll();
}
template
inline void DList::Invert()
{
if(m_nCount<=1) return;
Node *tmpNod,*curNod,*nextNod;
curNod=m_pNodeHead;
for(int i=1;i<=m_nCount;i++)
{
nextNod=curNod->next;
tmpNod=curNod->prior;
curNod->prior=curNod->next;
curNod->next=tmpNod;
curNod=nextNod;
}
tmpNod=m_pNodeHead;
m_pNodeHead=m_pNodeTail;
m_pNodeTail=tmpNod;
return;
}
//insert data before pos.
template
inline int DList::InsertBefore(const int pos, const T data)
{
int i;
int nRetPos;
Node *pTmpNode;
Node *pNewNode;
try
{
pNewNode = new Node;
}
catch(std::bad_alloc&)
{
nRetPos = 0;
return nRetPos;
}
pNewNode->data = data;
// if the list is empty, replace the head node with the new node.
if (NULL == m_pNodeHead)
{
pNewNode->prior = NULL;
pNewNode->next = NULL;
m_pNodeHead = pNewNode;
m_pNodeTail = pNewNode;
nRetPos = 1;
++m_nCount;
return nRetPos;
}
// is pos range valid?
ASSERT(1 <= pos && pos <= m_nCount);
// insert before head node?
if (1 == pos)
{
pNewNode->prior = NULL;
pNewNode->next = m_pNodeHead;
m_pNodeHead->prior = pNewNode;
m_pNodeHead = pNewNode;
nRetPos = 1;
++m_nCount;
return nRetPos;
}
// if the list is not empty and is not inserted before head node,
// seek to the pos of the list and insert the new node before it.
pTmpNode = m_pNodeHead;
for (i = 1; i < pos; ++i)
{
pTmpNode = pTmpNode->next;
}
pNewNode->next = pTmpNode;
pNewNode->prior = pTmpNode->prior;
pTmpNode->prior->next = pNewNode;
pTmpNode->prior = pNewNode;
// if tail node, must update m_pNodeTail
if (NULL == pNewNode->next)
{
m_pNodeTail = pNewNode;
}
nRetPos = pos;
++m_nCount;
return nRetPos;
}
//insert data after pos
template
inline int DList::InsertAfter(const int pos, const T data)
{
int i;
int nRetPos;
Node *pNewNode;
Node *pTmpNode;
try
{
pNewNode = new Node;
}
catch(std::bad_alloc&)
{
nRetPos = 0;
return nRetPos;
}
pNewNode->data = data;
// if the list is empty, replace the head node with the new node.
if (NULL == m_pNodeHead)
{
pNewNode->prior = NULL;
pNewNode->next = NULL;
m_pNodeHead = pNewNode;
m_pNodeTail = pNewNode;
nRetPos = 1;
++m_nCount;
return nRetPos;
}
// is pos range valid?
ASSERT(1 <= pos && pos <= m_nCount);
// if the list is not empty,
// seek to the pos of the list and insert the new node after it.
pTmpNode = m_pNodeHead;
for (i = 1; i < pos; ++i)
{
pTmpNode = pTmpNode->next;
}
pNewNode->next = pTmpNode->next;
pNewNode->prior = pTmpNode;
pTmpNode->next = pNewNode;
//modified by myself
// if tail node, must update m_pNodeTail
if(NULL==pNewNode->next)
{
m_pNodeTail = pNewNode;
}
else
{
pNewNode->next->prior=pNewNode;
}
nRetPos = pos + 1;
++m_nCount;
return nRetPos;
}
template
inline T& DList::GetAt(const int pos)
{
ASSERT(1 <= pos && pos <= m_nCount);
int i;
Node *pTmpNode = m_pNodeHead;
for (i = 1; i < pos; ++i)
{
pTmpNode = pTmpNode->next;
}
return pTmpNode->data;
}
template
inline T DList::GetAt(const int pos) const
{
ASSERT(1 <= pos && pos <= m_nCount);
int i;
Node *pTmpNode = m_pNodeHead;
for (i = 1; i < pos; ++i)
{
pTmpNode = pTmpNode->next;
}
return pTmpNode->data;
}
template
inline int DList::AddHead(const T data)
{
return InsertBefore(1, data);
}
template
inline int DList::AddTail(const T data)
{
return InsertAfter(GetCount(), data);
}
template
inline int DList::IsEmpty() const
{
return 0 == m_nCount;
}
template
inline int DList::GetCount() const
{
return m_nCount;
}
template
inline T& DList::GetTail()
{
ASSERT(0 != m_nCount);
return m_pNodeTail->data;
}
template
inline T DList::GetTail() const
{
ASSERT(0 != m_nCount);
return m_pNodeTail->data;
}
template
inline T& DList::GetHead()
{
ASSERT(0 != m_nCount);
return m_pNodeHead->data;
}
template
inline T DList::GetHead() const
{
ASSERT(0 != m_nCount);
return m_pNodeHead->data;
}
//as its name, delete the data at pos
template
inline void DList::RemoveAt(const int pos)
{
ASSERT(1 <= pos && pos <= m_nCount);
int i;
Node *pTmpNode = m_pNodeHead;
// head node?
if (1 == pos)
{
m_pNodeHead = m_pNodeHead->next;
if(m_pNodeHead)
{
m_pNodeHead->prior=NULL;
}
delete pTmpNode;
--m_nCount;
if (0 == m_nCount)
{
m_pNodeTail = NULL;
}
return;
}
//otherwise...
for (i = 1; i < pos; ++i)
{
pTmpNode = pTmpNode->next;
}
pTmpNode->prior->next = pTmpNode->next;
//last node?
if(pTmpNode->next)
{
pTmpNode->next->prior=pTmpNode->prior;
}
else
{
m_pNodeTail=pTmpNode->prior;
}
delete pTmpNode;
--m_nCount;
if (0 == m_nCount)
{
m_pNodeTail = NULL;
}
return;
}
template
inline void DList::RemoveHead()
{
ASSERT(0 != m_nCount);
RemoveAt(1);
}
template
inline void DList::RemoveTail()
{
ASSERT(0 != m_nCount);
RemoveAt(m_nCount);
}
template
inline void DList::RemoveAll()
{
int i;
int nCount;
Node *pTmpNode;
nCount = m_nCount;
for (i = 0; i < nCount; ++i)
{
pTmpNode = m_pNodeHead->next;
delete m_pNodeHead;
m_pNodeHead = pTmpNode;
}
m_pNodeHead=NULL;
m_pNodeTail=NULL;
m_nCount = 0;
}
template
inline void DList::SetAt(const int pos, T data)
{
ASSERT(1 <= pos && pos <= m_nCount);
int i;
Node *pTmpNode = m_pNodeHead;
for (i = 1; i < pos; ++i)
{
pTmpNode = pTmpNode->next;
}
pTmpNode->data = data;
}
template
inline int DList::Find(const T data) const
{
int i;
int nCount;
Node *pTmpNode = m_pNodeHead;
nCount = m_nCount;
for (i = 0; i < nCount; ++i)
{
if (data == pTmpNode->data)
return i + 1;
pTmpNode = pTmpNode->next;
}
return 0;
}
/*判断链表是否有环，如果有环则返回环的首结点位置，否则返回0*/
template
inline int DList::FindCircle() const
{
if(0==m_nCount)
{
return 0;
}
Node* p1=m_pNodeHead;
Node* p2=m_pNodeHead;
/*判断链表是否有环，当p1=p2时说明链表有环，程序跳出循环。如果p2一直走到链表尽头则说明没有环。*/
do{
if(p1!=NULL&&p2!=NULL&&p2->next!=NULL)
{
p1=p1->next;
p2=p2->next->next;
}
else
return 0;
}
while(p1!=p2);
/*求出环的起点节点，并将其返回*/
p2=m_pNodeHead;
while(p1!=p2)
{
p1=p1->next;
p2=p2->next;
}
int i;
p2=m_pNodeHead;
for(i=1;i<=m_nCount;i++)
{
if(p1==p2) break;
p2=p2->next;
}
return i;
}
/*判断两个链表是否交叉，如果交叉返回首个交叉节点位置（在本链表中的位置，而不是testlist中的位置），否则返回0。
假定：这两个链表本身均无环*/
template
inline int DList::FindCross(DList& testlist)
{
if(0==m_nCount||0==testlist.m_nCount)
{
return 0;
}
if(FindCircle()||testlist.FindCircle())
{
return 0;
}
/*将第二个链表接在第一个链表后面*/
Node* pTail=m_pNodeHead;
for(int i=1;inext;
}
pTail=testlist.m_pNodeHead;
m_nCount+=testlist.m_nCount;
int i=FindCircle();
pTail=NULL;
m_nCount-=testlist.m_nCount;
return i;
}
//get the data at pos and let pos=pos+1
template
inline T& DList::GetNext(int &pos)
{
ASSERT(0 != m_nCount);
ASSERT(1 <= pos && pos <= m_nCount);
int i;
Node *pTmpNode = m_pNodeHead;
for (i = 1; i < pos; ++i)
{
pTmpNode = pTmpNode->next;
}
++pos;
return pTmpNode->data;
}
//get the data at pos and let pos=pos-1
template
inline T& DList::GetPrev(int &pos)
{
ASSERT(0 != m_nCount);
ASSERT(1 <= pos && pos <= m_nCount);
int i;
Node *pTmpNode = m_pNodeHead;
for (i = 1; i < pos; ++i)
{
pTmpNode = pTmpNode->next;
}
--pos;
return pTmpNode->data;
}
#endif // __DOUBLE_LIST_H__