一、概念
(1)数组的线性序是由数组的下标决定的,链表中的顺序是由各对象中的指针所决定的
(2)链表结点结构
node *prev;
node *next;
int key;
(3)链表结点
node *head;
node *nil;//哨兵
(4)对链表的操作
LIST-SEARCH(L, k)
LIST-INSERT(L, x)
LIST-DELETE(L, x)
(5)哨兵是个哑对象,可以简化边界条件
二、代码
(1)没有哨兵的情况
[cpp] view plain copy
- //链表结点结构
- struct node
- {
- node *pre;
- node *next;
- int key;
- //构造函数
- node(int x):pre(NULL),next(NULL),key(x){}
- };
- //链表结构
- struct List
- {
- node *head;
- List():head(NULL){}
- };
- //打印
- void List_Print(List *L)
- {
- node *p = L->head;
- while(p)
- {
- cout<<p->key<<' ';
- p = p->next;
- }
- cout<<endl;
- }
- //搜索,找出L中第一个关键字为k的结点,没有则返回NULL
- node *List_Search(List *L, int k)
- {
- node *x = L->head;
- while(x != NULL && x->key!=k)
- x = x->next;
- return x;
- }
- //插入
- void List_Insert(List *L, node *x)
- {
- //插入到表的前端
- x->next = L->head;
- if(L->head != NULL)
- L->head->pre = x;
- L->head = x;
- x->pre = NULL;
- }
- //删除
- void List_Delete(List *L, node* x)
- {
- if(x->pre != NULL)
- x->pre->next = x->next;
- else
- L->head = x->next;
- if(x->next != NULL)
- x->next->pre = x->pre;
- delete x;
- }
//链表结点结构 struct node { node *pre; node *next; int key; //构造函数 node(int x):pre(NULL),next(NULL),key(x){} }; //链表结构 struct List { node *head; List():head(NULL){} }; //打印 void List_Print(List *L) { node *p = L->head; while(p) { cout<<p->key<<' '; p = p->next; } cout<<endl; } //搜索,找出L中第一个关键字为k的结点,没有则返回NULL node *List_Search(List *L, int k) { node *x = L->head; while(x != NULL && x->key!=k) x = x->next; return x; } //插入 void List_Insert(List *L, node *x) { //插入到表的前端 x->next = L->head; if(L->head != NULL) L->head->pre = x; L->head = x; x->pre = NULL; } //删除 void List_Delete(List *L, node* x) { if(x->pre != NULL) x->pre->next = x->next; else L->head = x->next; if(x->next != NULL) x->next->pre = x->pre; delete x; }
(2)有哨兵的情况
[cpp] view plain copy
- //链表结点结构
- struct node
- {
- node *pre;
- node *next;
- int key;
- //构造函数
- node(int x):pre(NULL),next(NULL),key(x){}
- };
- //链表结构
- struct List
- {
- node *nil;//哨兵
- List()
- {
- nil = new node(0);
- nil->next = nil;
- nil->pre = nil;
- }
- };
- //打印
- void List_Print(List *L)
- {
- node *p = L->nil->next;
- while(p != L->nil)
- {
- cout<<p->key<<' ';
- p = p->next;
- }
- cout<<endl;
- }
- //搜索,找出L中第一个关键字为k的结点,没有则返回NULL
- node *List_Search(List *L, int k)
- {
- node *x = L->nil->next;
- while(x != L->nil && x->key!=k)
- x = x->next;
- return x;
- }
- //插入
- void List_Insert(List *L, node *x)
- {
- //插入到表的前端
- x->next = L->nil->next;
- L->nil->next->pre = x;
- L->nil->next = x;
- x->pre = L->nil;
- }
- //删除
- void List_Delete(List *L, node* x)
- {
- x->pre->next = x->next;
- x->next->pre = x->pre;
- delete x;
- }
//链表结点结构 struct node { node *pre; node *next; int key; //构造函数 node(int x):pre(NULL),next(NULL),key(x){} }; //链表结构 struct List { node *nil;//哨兵 List() { nil = new node(0); nil->next = nil; nil->pre = nil; } }; //打印 void List_Print(List *L) { node *p = L->nil->next; while(p != L->nil) { cout<<p->key<<' '; p = p->next; } cout<<endl; } //搜索,找出L中第一个关键字为k的结点,没有则返回NULL node *List_Search(List *L, int k) { node *x = L->nil->next; while(x != L->nil && x->key!=k) x = x->next; return x; } //插入 void List_Insert(List *L, node *x) { //插入到表的前端 x->next = L->nil->next; L->nil->next->pre = x; L->nil->next = x; x->pre = L->nil; } //删除 void List_Delete(List *L, node* x) { x->pre->next = x->next; x->next->pre = x->pre; delete x; }
三、练习
[cpp] view plain copy
- 10.2-1
- 能,能
- 10.2-2
- //结点
- struct node
- {
- node *pre;//为了方便实现出栈操作
- node *next;
- int key;
- node(int x):pre(NULL),next(NULL),key(x){}
- };
- //链式栈
- struct list
- {
- node *Head;//栈的起始结点
- node *Top;//栈顶指针
- list(){Head = new node(0);Top = Head;}
- };
- //打印栈中的元素
- void Print(list *L)
- {
- node *p = L->Head->next;
- while(p)
- {
- cout<<p->key<<' ';
- p = p->next;
- }
- cout<<endl;
- }
- //入栈
- void Push(list *L, int x)
- {
- //构造一个新的结点
- node *A = new node(x);
- //链入到栈顶位置,修改指针
- L->Top->next = A;
- A->pre = L->Top;
- L->Top = A;
- }
- //出栈
- int Pop(list *L)
- {
- if(L->Head == L->Top)
- {
- cout<<"error:underflow"<<endl;
- return -1;
- }
- //取出栈顶元素
- int ret = L->Top->key;
- //修改指针
- node *A = L->Top;
- L->Top = A->pre;
- L->Top->next = NULL;
- delete A;
- return ret;
- }
- 10.2-3
- //结点
- struct node
- {
- node *next;
- int key;
- node(int x):next(NULL),key(x){}
- };
- //链式队列
- struct list
- {
- node *Head;//头指针
- node *Tail;//尾指针
- list(){Head = new node(0);Tail = Head;}
- };
- //打印
- void Print(list *L)
- {
- node *p = L->Head->next;
- while(p)
- {
- cout<<p->key<<' ';
- p = p->next;
- }
- cout<<endl;
- }
- //入队列
- void Enqueue(list *L, int x)
- {
- //构造一个新的结点
- node *A = new node(x);
- //链入尾部,修改指针
- L->Tail->next = A;
- L->Tail = A;
- }
- //出队列
- int Dequeue(list *L)
- {
- if(L->Head == L->Tail)
- {
- cout<<"error:underflow"<<endl;
- return -1;
- }
- //取出队头结点,修改指针
- node *A = L->Head->next;
- int ret = A->key;
- L->Head->next = A->next;
- if(A == L->Tail)
- L->Tail = L->Head;
- delete A;
- return ret;
- }
- 10.2-4
- 把哨兵的值置为一个不可能与x相等的值
10.2-1 能,能 10.2-2 //结点 struct node { node *pre;//为了方便实现出栈操作 node *next; int key; node(int x):pre(NULL),next(NULL),key(x){} }; //链式栈 struct list { node *Head;//栈的起始结点 node *Top;//栈顶指针 list(){Head = new node(0);Top = Head;} }; //打印栈中的元素 void Print(list *L) { node *p = L->Head->next; while(p) { cout<<p->key<<' '; p = p->next; } cout<<endl; } //入栈 void Push(list *L, int x) { //构造一个新的结点 node *A = new node(x); //链入到栈顶位置,修改指针 L->Top->next = A; A->pre = L->Top; L->Top = A; } //出栈 int Pop(list *L) { if(L->Head == L->Top) { cout<<"error:underflow"<<endl; return -1; } //取出栈顶元素 int ret = L->Top->key; //修改指针 node *A = L->Top; L->Top = A->pre; L->Top->next = NULL; delete A; return ret; } 10.2-3 //结点 struct node { node *next; int key; node(int x):next(NULL),key(x){} }; //链式队列 struct list { node *Head;//头指针 node *Tail;//尾指针 list(){Head = new node(0);Tail = Head;} }; //打印 void Print(list *L) { node *p = L->Head->next; while(p) { cout<<p->key<<' '; p = p->next; } cout<<endl; } //入队列 void Enqueue(list *L, int x) { //构造一个新的结点 node *A = new node(x); //链入尾部,修改指针 L->Tail->next = A; L->Tail = A; } //出队列 int Dequeue(list *L) { if(L->Head == L->Tail) { cout<<"error:underflow"<<endl; return -1; } //取出队头结点,修改指针 node *A = L->Head->next; int ret = A->key; L->Head->next = A->next; if(A == L->Tail) L->Tail = L->Head; delete A; return ret; } 10.2-4 把哨兵的值置为一个不可能与x相等的值
10.2-5
见算法导论
10.2-5 环形链表实现字典操作INSERT、DELETE、SEARCH
10.2-6
使用带尾指针的链表,令A的尾指针为tail,tail->next=B
10.2-7
[cpp] view plain copy
- //逆转
- void Reverse(list *L)
- {
- node *p = NULL, *q = L->Head, *r;
- //依次修改指针,让q是p->next,令q->next=p
- while(1)
- {
- r = q->next;
- q->next = p;
- if(r == NULL)
- {
- L->Head = q;
- break;
- }
- p = q;
- q = r;
- }
- }
时间: 2024-09-27 02:12:06