数据结构和算法学习总结03 线性表---单链表

单链表

单链表是一种链式存取的数据结构，用一组地址任意的存储单元存放线性表中的数据元素。

单链表的优点在于 当大量的进行插入和删除操作时，它的效率是比顺序表高的。

              缺点在于 当只是进行读取元素时，它的效率比顺序表底。

以下为单链表（C++）的代码:

#include <stdio.h>
#include <iostream>
using namespace std;

typedef struct ListNode
{
    int data;
    struct ListNode *next;
} Node;

class SingleList
{
public:
    SingleList()
    {
        head = new Node;
        head->data = 0;
        head->next = NULL;
    }
    ~SingleList() {delete[] head;}
    
    void CreateList(int n);                    //创建链表 
    void InsertNode(int position, int d);    //在指定位置插入结点 
    void DeleteNode(int position);            //删除指定位置结点 
    int CheckList(int position);            //查询指定位置
    bool IsEmpty();                            //判断链表是否为空 
    int GetLength();                        //链表长度 
    void ReverseList();                        //单链表反转/逆序
    void DestroyList();                        //销毁整个链表     头指针为空
    void ClearList();                        //清空链表           头指针不为空
    void OutputList();                        //遍历链表 
    
private:
    Node *head;
};

void SingleList::CreateList(int n) 
{ 
    //尾插法创建单链表 
    if(n<0)
    {
        cout<<"输入节点数量错误"<<endl;
        exit(0);
    }
    else
    {
        Node *tempN, *newN;
        tempN = head;
        while(n-->0)
        {
            newN=new Node;
            cout<<"请输入结点值："<<endl;
            cin>>newN->data;
            newN->next = NULL;
            tempN->next = newN;
            tempN = newN;
        }
    }
    //头插法创建单链表 输入顺序和链表顺序相反
    /*
    if(n<0)
    {
    cout<<"输入节点数量错误"<<endl;
    exit(0);
    }
    else
    {
    Node *tempN, *newN;
    tempN = new Node;
    head->next = NULL;
    while(n-->0)
    {
    newN=new Node;
    cout<<"请输入结点值："<<endl;
    cin>>newN->data;
    newN->next = head->next;
    head->next = newN;
    }
    }
    */
}

void SingleList::InsertNode(int position, int d)
{
    if(position<0||position >GetLength()+1)
    {
        cout<<"输入位置错误！"<<endl;
        exit(0);
    }
    else
    {
        Node *tempN, *newN;
        tempN = head;
        newN = new Node;
        newN->data = d;
        newN->next = NULL;
        int i = 1;
        while(i<position)
        {
            tempN = tempN->next;
            i++;
        }
        newN->next = tempN->next;
        tempN->next = newN;
    }
}
void SingleList::DeleteNode(int position)
{
    if (position < 0 || position > GetLength()) { 
        cout << "输入位置错误！" << endl; 
        exit(0); 
    } 
    else
    {
        Node *tempN,*deleteN;
        tempN = head;
        int i = 1;
        while(i<position)
        {
            tempN = tempN->next;
            i++;
        }
        deleteN = tempN->next;
        tempN->next = deleteN->next;
        delete deleteN;
    }
}

bool SingleList::IsEmpty() { 
    if (head->next == NULL) 
        return true; 
    else 
        return false; 
}

int SingleList::GetLength() { 
    Node *p = head->next; 
    int n = 0; 
    while (p != NULL) { 
        n++; 
        p = p->next; 
    } 
    return n; 
}

void SingleList::OutputList() { 
    Node *p = head->next; 
    while (p != NULL) { 
        cout << p->data << " "; 
        p = p->next; 
    } 
    cout << endl; 
}

void SingleList::DestroyList() { 
    Node *p; 
    while(head)  
    {  
        p=head->next;  
        delete head;  
        head=p;
    }  
}

void SingleList::ClearList()
{
    Node *p,*q;
    p=head->next;          
    while(p)               
    {    
        q=p->next;
        delete p;
        p=q;
    }
    head->next=NULL;        
}

int SingleList::CheckList(int position) //查询 
{ 
    int i; 
    Node *p; 
    p = head->next; 
    i=1; 
    while(p&&i<position) 
    { 
        p = p->next; 
        i++; 
    } 
    if(!p || i>position) 
        cout<<"查询的元素不存在!"<<endl; 
    return p->data;
}

void SingleList::ReverseList()
{
    Node *current, *p;
    current = head->next;
    while (current->next) 
    {
        p = current->next;
        current->next = p->next;
        p->next = head->next;
        head->next = p;
    }
}

int main() 
{ 
    int num,v,p; 
    cout<<"********************************************"<<endl; 
    cout<<" 【1】创建 【2】插入" <<endl; 
    cout<<" 【3】删除 【4】查询" <<endl; 
    cout<<" 【5】清空 【6】翻转" <<endl; 
    cout<<" 【7】遍历 【8】退出" <<endl; 
    cout<<"********************************************"<<endl; 
    cout<<"请输入你的操作序号："; 
    
    SingleList list;
    while(1)
    {
        cin>>num; 
        switch(num) 
        { 
        case 1: 
            cout<<"要创建的链表长度:"<<endl;
            cin>>v;
            list.CreateList(v); 
            cout<<"创建成功"<<endl;
            break; 
        case 2: 
            cout<<"要插入的元素的位置:"<<endl;
            cin>>p;
            cout<<"要插入的元素:"<<endl;
            cin>>v;
            list.InsertNode(p,v); 
            break; 
        case 3: 
            cout<<"要删除的元素的位置:"<<endl;
            cin>>p;
            list.DeleteNode(p); //删除 
            break; 
        case 4: 
            cout<<"要查询的元素的位置:"<<endl;
            cin>>p;
            cout<<"查询结果"<<list.CheckList(p)<<endl; //查询 
            break; 
        case 5: 
            list.ClearList(); //清空 
            break; 
        case 6: 
            list.ReverseList(); //翻转 
            break; 
        case 7: 
            list.OutputList(); //显示 
            break; 
        case 8: 
            list.DestroyList(); //销毁 
            exit(0); 
            break; 
        } 
        cout<<"请输入你的操作序号："; 
    }
}