20140720 链表反转、合并、二叉树镜像-优快云博客

本文介绍了链表的基本操作，包括链表的反转和两个有序链表的合并，并探讨了如何检查两棵二叉树之间是否存在子结构关系。

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1、链表的反转

#include<iostream>
#include<malloc.h>
using namespace std;
typedef struct ListNode
{
    int data;
    struct ListNode * Next;
}ListNode;

ListNode *ReverseList(ListNode *pHead)
{
    ListNode *PReverseHead=NULL;
    ListNode *pBefore=NULL;
    ListNode *pAfter=NULL;
    ListNode *pNode=pHead;
    while(pNode!=NULL)
    {
        pAfter=pNode->Next;

        if(pNode->Next==NULL)
        {PReverseHead=pNode;}
        pNode->Next=pBefore;
        pBefore=pNode;
        pNode=pAfter;
    }
    return PReverseHead;
}

ListNode *CreateList()
{
    int x=0;
    cout<<"input data:";  cin>>x;
    if(x==0)
        return NULL;
    ListNode *pHead=(ListNode *)malloc(sizeof(ListNode));
    pHead->data=x;
    pHead->Next=NULL;
    ListNode *rear=pHead;
    cout<<"input data:";    cin>>x;
    while(x!=0)
    {
        ListNode *p=(ListNode *)malloc(sizeof(ListNode));
        p->data=x;
        p->Next=NULL;
        rear->Next=p;
        rear=p;
        cout<<"input data:";
        cin>>x;
    }
    return pHead;
}

void PrintList(ListNode *pHead)
{
    ListNode *p=pHead;
    while(p!=NULL)
    {
        cout<<p->data<<" ";
        p=p->Next;
    }
}
void main()
{
    ListNode *pHead=CreateList();
    PrintList(pHead);
    ListNode *pReverseHead=ReverseList(pHead);

    PrintList(pReverseHead);
}

2、合并链表

#include<iostream>
#include<malloc.h>
using namespace std;
typedef struct ListNode
{
    int data;
    struct ListNode * Next;
}ListNode;

ListNode *MergeList(ListNode *pHead1,ListNode *pHead2)
{
    if(pHead2==NULL)
        return pHead1;
    if(pHead1==NULL)
        return pHead2;
    ListNode *pMergeHead=NULL;
    if(pHead1->data<pHead2->data)
    {
        pMergeHead=pHead1;
        pHead1->Next=MergeList(pHead1->Next,pHead2);
    }
    else 
    {
        pMergeHead=pHead2;
        pHead2->Next=MergeList(pHead1,pHead2->Next);
    }
    return pMergeHead;
}

ListNode *CreateList()
{
    int x=0;
    cout<<"input data:";  cin>>x;
    if(x==0)
        return NULL;
    ListNode *pHead=(ListNode *)malloc(sizeof(ListNode));
    pHead->data=x;
    pHead->Next=NULL;
    ListNode *rear=pHead;
    cout<<"input data:";    cin>>x;
    while(x!=0)
    {
        ListNode *p=(ListNode *)malloc(sizeof(ListNode));
        p->data=x;
        p->Next=NULL;
        rear->Next=p;
        rear=p;
        cout<<"input data:";
        cin>>x;
    }
    return pHead;
}

void PrintList(ListNode *pHead)
{
    ListNode *p=pHead;
    while(p!=NULL)
    {
        cout<<p->data<<" ";
        p=p->Next;
    }
}
void main()
{
    ListNode *pHead1=CreateList();
    ListNode *pHead2=CreateList();
    ListNode *pMergeNode=MergeList(pHead1,pHead2);
    PrintList(pMergeNode);
}