数据结构篇：单链表倒置（带头结点/不带头结点）

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带头结点

初始化如图

1.我们需要把1这个结点作为最后一个结点，所以要把1的next指向NULL

h->next->next = nullptr;

 

2.然后我们要新建结点，指向HeadNext的下一位,并把HeadNext的下一位指向HeadPre，

Inode *tempNode = HeadNext->next;
HeadNext->next = HeadPre;

 

3. HeadPre指向HeadNext为下一次循环做准备

HeadPre = HeadNext;

 4.如果tempNode为空，说明HeadNext已经是最后一个结点，把头结点的下一位指向HeadNext

if (tempNode == nullptr)
{
    h->next = HeadPre;
}

5.将HeadNext往后移一位 

HeadNext = tempNode;

 

6.继续循环，直至HeadNext为空

完整函数

Inode *Test::ReserveLink(Inode *h) {
    Inode *HeadNext, *HeadPre;
    HeadNext = h->next->next;
    HeadPre = h->next;
    h->next->next = nullptr;
    while (HeadNext)
    {
        Inode *tempNode = HeadNext->next;
        HeadNext->next = HeadPre;
        HeadPre = HeadNext;
        if (tempNode == nullptr)
        {
            h->next = HeadPre;
        }
        HeadNext = tempNode;
    }
    return h;
}

运行截图

完整程序

#include <iostream>

using namespace std;

typedef struct Link {
    int num;
    Link *next;
} Inode;

class Test {
public :
    Inode *t_CreateList(Inode *Head, int n);//尾插法建立单链表
    void ShowLink(Inode *h);

    Inode *ReserveLink(Inode *h);
};

Inode *Test::t_CreateList(Inode *Head, int n) {
    Inode *p = Head;
    for (int i = 0; i < n; i++)
    {
        Inode *s = new Inode;
        cin >> s->num;
        s->next = p->next;
        p->next = s;
        p = s;
    }
    return Head;
}


void Test::ShowLink(Inode *h) {
    Inode *p = h;
    cout<<"单链表为："<<endl;
    while (p->next)
    {
        cout << p->next->num <<"-->";
        p = p->next;
    }
    cout<<endl;
}

Inode *Test::ReserveLink(Inode *h) {
    Inode *HeadNext, *HeadPre;
    HeadNext = h->next->next;
    HeadPre = h->next;
    h->next->next = nullptr;
    while (HeadNext)
    {
        Inode *tempNode = HeadNext->next;
        HeadNext->next = HeadPre;
        HeadPre = HeadNext;
        if (tempNode == nullptr)
        {
            h->next = HeadPre;
        }
        HeadNext = tempNode;
    }
    return h;
}

int main() {
    Test test;
    Inode *Head = new Inode;
    Head->next = NULL;
    int num;
    cout << "您想要创建几个元素的单链表？请输入：" << endl;
    cin >> num;
    Head = test.t_CreateList(Head, num);
    test.ShowLink(Head);
    Head = test.ReserveLink(Head);
    test.ShowLink(Head);
    return 0;
}

不含头结点

Inode *Test::ReserveLink(Inode *h) {
    Inode *HeadNext, *HeadPre;
    HeadNext = h->next;
    HeadPre = h;
    h->next = nullptr;
    while (HeadNext)
    {
        Inode *tempNode = HeadNext->next;
        HeadNext->next = HeadPre;
        HeadPre = HeadNext;
        if (tempNode == nullptr)
        {
            h = HeadPre;
        }
        HeadNext = tempNode;
    }
    return h;
}