HihoCoder1371 - 翻转链表 - 模板题

题目链接

https://vjudge.net/problem/HihoCoder-1371

迭代法

#include<bits/stdc++.h>
using namespace std;

// 迭代法

struct node
{
    int w;
    node *nex;
    node(int w)
    {
        this->w=w;
        this->nex=NULL;
    }
};

int main()
{
    int n;
    while(cin>>n)
    {
        if(n==-1) break;
        // dummy=new node();
        node dummy(0); //其他俩会报错
        // node *dummy = new node(0);
        node *cur=&dummy;
        for(int i=0; i<n; i++)
        {
            int x;
            cin>>x;
            cur->nex=new node(x);
            cur=cur->nex;
        }
        node *head=dummy.nex;
        node *pre=NULL;
        while(head)
        {
            node *nex=head->nex;
            head->nex=pre;
            pre=head,head=nex;
        }
        head=pre;
        while(head->nex)
        {
            cout<<head->w<<" ";
            head=head->nex;
        }
        cout<<head->w<<endl;
    }
    return 0;
}

递归法

#include<iostream>
#include<string.h>

using namespace std;
#define inf 0x3f3f3f3f
typedef long long ll;

struct node
{
    int w;
    node*next;
    node(int w)
    {
        this->w=w;
        this->next=NULL;
    }
};


node*reverseList(node *head)
{
    if(head==NULL||head->next==NULL) return head;
    node*pre=NULL,*cur=head;  // cur指向链表中的头结点
    while(cur!=NULL)
    {
        node*next=cur->next;// 更换当前结点的箭头方向  pointer 用-> 不用.
        cur->next=pre;
        pre=cur;
        cur=next;
    }
    return pre;
}

int main()
{
    int n;
    while(cin>>n,n!=-1)
    {
        node dummy(0),*cur=&dummy;
        for(int i=0;i<n;i++)
        {
            int x;
            cin>>x;
            cur->next=new node(x);
            cur=cur->next;
        }
        node *head=dummy.next,*pre=NULL;
        head=reverseList(head);
        while(head->next)
        {
            cout<<head->w<<" ";
            head=head->next;
        }
        cout<<head->w<<endl;
    }
    return 0;
}