qfedu-cpp-level/day3/homework/h5.cpp

// 创建一个名为 LinkedList 的类，实现链表的基本操作，包括插入节点、删除节点和反转链表等。
// 【提示】单向链表
#include <iostream>
#include <cstring>
#include <cstdlib>

using namespace std;

class Node
{
public:
    int data;
    Node *next;

public:
    Node(int value)
    {
        this->data = value;
        this->next = NULL;
    }
};

class LinkedList
{
private:
    Node *head;

public:
    LinkedList()
    {
        head = NULL; // 初始头结点
    }

public:
    Node *insertNode(int insValue);
    Node *deleteNode(int delValue);
    Node *reverseLinkedList();
    void print();
};

Node *LinkedList::insertNode(int insValue)
{
    Node *newNode = new Node(insValue);

    if (NULL == head)
        head = newNode;

    Node *p = head;
    while (p->next != NULL)
    {
        p = p->next;
    }
    p->next = newNode;
    return head;
}

Node *LinkedList::deleteNode(int delValue)
{
    if (NULL == head)
    {
        cout << "不存在链表，删除失败" << endl;
        return head;
    }

    if (head->data == delValue) // 当删除的节点是头节点时
    {
        Node *temp = head;
        head = head->next;
        delete temp;
        return head;
    }

    Node *p = head;
    while (p->next != NULL)
    {
        if (p->next->data == delValue)
        {
            Node *temp = p->next;
            p->next = temp->next;
            delete temp;
        }
        p = p->next;
    }

    if (p != NULL && p->data == delValue) // 处理最后一个节点的情况
    {
        delete p;
        p = NULL;
    }
    return head;
}

Node *LinkedList::reverseLinkedList()
{
    Node *p = head;
    Node *new_head = NULL;
    Node *p_next = NULL;
    while (p != NULL)
    {
        p_next = p->next;
        p->next = new_head;
        new_head = p;
        p = p_next;
    }

    head = new_head; // 新头指针
    return head;
}

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

int main()
{
    LinkedList list;

    // 插入节点
    list.insertNode(1);
    list.insertNode(3);
    list.insertNode(8);
    list.insertNode(2);

    // 测试打印
    cout << "原始链表: ";
    list.print();
    cout << endl;

    // 删除节点
    list.deleteNode(3);
    cout << "删除3后的链表: ";
    list.print();
    cout << endl;

    // 反转链表
    list.reverseLinkedList();
    cout << "反序链表后: ";
    list.print();
    cout << endl;
    return 0;
}