数据结构之实用单链表(参考整理严蔚敏数据结构)

#include<iostream>
using namespace std;

typedef int ElemType;

typedef struct Node
{
ElemType data;
Node *pNext;
}Node,*Link;

typedef struct LinkList
{
Link pHead;
Link pTail;
int Length;
}LinkList;

void MakeNode(Link &p, ElemType e)
{
p = new Node;
p->data = e;
p->pNext = NULL;
}

void FreeNode(Link &p)
{
delete p;
p = NULL;
}

void InitList(LinkList &L)
{
Link p;
p = new Node;
p->pNext = NULL;
L.pHead = p;
L.pTail = p;
L.Length = 0;
}

void ClearList(LinkList &L)
{
Link p, q;
if (L.pHead != L.pTail)//or L.Length!=0
{
p = L.pHead->pNext;
q = L.pHead->pNext;
L.pHead->pNext = NULL;
while (q!= L.pTail)
{
q = p->pNext;
delete p;
p = q;
}
delete p;//or delete q;
p = q = NULL;
L.pTail = L.pHead;
L.Length = 0;
}
}

void DestroyList(LinkList &L)
{
ClearList(L);
FreeNode(L.pHead);
L.pTail = NULL;
L.pHead = NULL;
L.Length = 0;
}

void InsFront(LinkList &L, Link h, Link s)
{// h指向L的一个结点(包括头结点),插入结点成为h后第一个结点
s->pNext = h->pNext;
h->pNext = s;
if (L.pTail == h) // h指向尾结点
L.pTail = h->pNext; // 修改尾指针
L.Length++;
}

bool RemoveFront(LinkList &L, Link h, Link &q)
{// h指向L的一个结点(包括头结点),移除h后面第一个结点并将该结点交给q处理
q = h->pNext;
if (q)// 以防止:链表为空或者h指向尾结点
{
h->pNext = q->pNext;
if (!(h->pNext))//删除结点为尾结点
L.pTail = h;
L.Length--;
return true;
}
else
return false;
}

bool RemoveListTail(LinkList &L, Link &q)
{// 移除线性链表L中的尾结点并以q返回，改变链表L的尾指针指向新的尾结点
Link p = L.pHead;
if (L.Length==0)
{
q = NULL;
return false;
}
else
{
while (p->pNext != L.pTail)
p = p->pNext;//p指向倒数第二个结点
q = L.pTail;
p->pNext = NULL;
L.pTail = p;
L.Length--;
return true;
}
}

void ListTailAppend(LinkList &L, Link s)
{// 将指针s(s->data为第一个数据元素)所指(彼此以指针相链,以NULL结尾)的
// 一串结点链接在线性链表L的最后一个结点之后,并改变链表L的尾指针指向新
// 的尾结点
int i = 1;
L.pTail->pNext = s;
while (s->pNext)
{
s = s->pNext;
++i;
}
L.pTail = s;
L.Length += i;
}

Link PriorPos(LinkList L, Link p)
{ // 已知p指向线性链表L中的一个结点，返回p所指结点的直接前驱的指针
// 若无前驱，则返回NULL
Link q;
q = L.pHead->pNext;//指向第一个结点
if (p==L.pHead)
return NULL;
else if (p==q)
return L.pHead;
else
{
while (q->pNext != p)// q不是p的直接前驱
q = q->pNext;
return q;
}
}

bool InsBefore(LinkList &L, Link &p, Link s)
{// 已知p指向线性链表L中的一个结点(包括头结点)，将s所指结点插入在p所指结点之前，
// 并修改指针p指向新插入的结点
Link q;
q = PriorPos(L, p);
if (!q)
return false;
else
{
s->pNext = p;
q->pNext = s;
p = s;
L.Length++;
return true;
}
}

void InsAfter(LinkList &L, Link &p, Link s)
{// 已知p指向线性链表L中的一个结点(包括头结点)，将s所指结点插入在p所指结点之后，
// 并修改指针p指向新插入的结点
if (p == L.pTail)// 修改尾指针
L.pTail = s;
s->pNext = p->pNext;
p->pNext = s;
p = s;
L.Length++;
}

int ListLength(LinkList L)
{
return L.Length;
}

bool ListEmpty(LinkList L)
{
if (L.Length == 0)
return true;
else
return false;
}

void SetCurElem(Link &p, ElemType e)
{
p->data = e;
}

ElemType GetCurElem(Link p)
{
return p->data;
}

Link GetHead(LinkList L)
{
return L.pHead;
}

Link GetTail(LinkList L)
{
return L.pTail;
}

Link NextPos(Link p)
{
return p->pNext;
}

bool LocatePos(LinkList L, int pos, Link &p)
{//pos==0为头结点
int i=0;
if (pos<0 ||pos>L.Length)
return false;
else
{
p = L.pHead;
while (i < pos)
{
p = p->pNext;
++i;
}
return true;
}
}

Link LocateElem(LinkList L, ElemType e)
{
Link p = L.pHead;
do
p = p->pNext;
while (p&&p->data != e);
return p;
}

void ListPrint(LinkList L)
{
Link p = L.pHead->pNext;
int i = 1;
while (i <= L.Length)
{
cout <<p->data<< " ";
p = p->pNext;
++i;
}
cout << endl;
}

int main(void)
{
Link p, h;
LinkList L;
int i, j;
InitList(L);
for (i = 1; i <= 5; ++i)
{
MakeNode(p, i);
InsFront(L, L.pTail, p);
}
ListPrint(L);
for (i =1; i <= 6; ++i)
{
if (LocatePos(L, i, p))
cout << "存在" << p->data << " ";
else
cout << "不存在!" << endl;
}
for (i = 0; i <= 6; ++i)
{
p = LocateElem(L, i);
if (p)
cout << "存在" << p->data << " ";
else
cout << "不存在!" <<" ";
}
cout << endl;
for (i = 1; i <= 6; ++i)
{
RemoveFront(L, L.pHead, p);
if (p)
cout << GetCurElem(p) << " ";
else
cout << "The List is Empty!" << endl;
}
cout << ListLength(L) << endl;
if (ListEmpty(L))
cout << "The List is Empty!" << endl;
MakeNode(p, 14);
for (i = 6; i >= 1; --i)
{//逆序
MakeNode(h, 2 * i);
h ->pNext = p;
p = h;
}
ListTailAppend(L, h);
ListPrint(L);
for(i = 1; i <= 6; ++i)
{
LocatePos(L, i, p);
h = PriorPos(L, p);
if (h == L.pHead)
cout << p->data << "头结点" << endl;
else if (!h)
cout << p->data << "无前驱!" << endl;
else
cout << p->data << " " << h->data << endl;
}
cout << endl;
j = ListLength(L);
for (i = j; i>=0; --i)
{
LocatePos(L, i, p);
h = NextPos(p);
if (h)
{
if (p==L.pHead)
cout<<"头结点 "<<h->data<<endl;
else
cout << p->data << " " << h->data << endl;
}
else
cout << p->data << " 无后继" << endl;
}
cout << ListLength(L) << endl;
if (!ListEmpty(L))
cout << "Not Empty!" << endl;
p = GetTail(L);
SetCurElem(p, 18);
cout <<GetCurElem(GetHead(L)->pNext)<< " " << GetCurElem(p)<<endl;
MakeNode(h, 16);
InsBefore(L, p, h);
p = p->pNext;// p恢复为尾结点
MakeNode(h, 20);
InsAfter(L, p, h);
ListPrint(L);
j = ListLength(L);
cout << j << endl;
DestroyList(L);
cout << L.pHead << endl;
cout << L.pTail << endl;
cout << L.Length << endl;
return(0);
}