两个单链表合并问题

来源：互联网发布：minitab软件编辑：程序博客网时间：2024/06/03 19:42

链表的结点如下所示，已知两个链表head1 和head2 各自有序，请把它们合并成一个链表依然有序。

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

单链表合并代码，非递归方式

Node * Merge(Node *head1 , Node *head2){    if ( head1 == NULL )   //head1为空         return head2 ;    if ( head2 == NULL)    //head2为空         return head1 ;    Node *head = NULL ;    Node *p1 = NULL;    Node *p2 = NULL;    //数据链表第一个结点小的做首结点     if ( head1->data < head2->data )       {        head = head1 ;        p1 = head1->next;        p2 = head2 ;    }    else    {        head = head2 ;        p2 = head2->next ;        p1 = head1 ;    }    Node *pcurrent = head ;    //当p1移到末尾或p2移到末尾     while ( p1 != NULL && p2 != NULL)    {        if ( p1->data <= p2->data )        {            pcurrent->next = p1 ;            pcurrent = p1 ;            p1 = p1->next ;        }        else        {            pcurrent->next = p2 ;            pcurrent = p2 ;            p2 = p2->next ;        }    }    //p1没有移到末尾，将p1添加到新链表后面     if ( p1 != NULL )        pcurrent->next = p1 ;    //p2没有移到末尾，将p2添加到新链表后面          if ( p2 != NULL )        pcurrent->next = p2 ;    return head ;}

单链表合并代码，递归方式

Node * MergeRecursive(Node *head1 , Node *head2){    if ( head1 == NULL )        return head2 ;    if ( head2 == NULL)        return head1 ;    Node *head = NULL ;    if ( head1->data < head2->data )    {        head = head1 ;        head->next = MergeRecursive(head1->next,head2);    }    else    {        head = head2 ;        head->next = MergeRecursive(head1,head2->next);    }    return head ;}

测试代码如下所示

#include <iostream>using namespace std;struct Node{    int data ;    Node *next ;};typedef struct Node Node ;//创建链表节点Node* CreateNode(){    Node *head = NULL;     Node *pnew = NULL;    Node *tail = NULL;    int d;     while(1)    {        cin >> d;        if (d==0)            break;        pnew = new Node;        pnew->data = d;        pnew->next = NULL;        if(head == NULL)        {            head = pnew;            tail = pnew;        }        else        {            tail->next = pnew;            tail = pnew;        }   }    return head;}void PrintList(Node *head){    if (head== NULL)        return ;    while(head)    {        cout << head->data << "  ";        head = head->next;    }    cout << endl;}//单链表合并，非递归方式 Node * Merge(Node *head1 , Node *head2){    if ( head1 == NULL )   //head1为空         return head2 ;    if ( head2 == NULL)    //head2为空         return head1 ;    Node *head = NULL ;    Node *p1 = NULL;    Node *p2 = NULL;    //数据链表第一个结点小的做首结点     if ( head1->data < head2->data )       {        head = head1 ;        p1 = head1->next;        p2 = head2 ;    }    else    {        head = head2 ;        p2 = head2->next ;        p1 = head1 ;    }    Node *pcurrent = head ;    //当p1移到末尾或p2移到末尾     while ( p1 != NULL && p2 != NULL)    {        if ( p1->data <= p2->data )        {            pcurrent->next = p1 ;            pcurrent = p1 ;            p1 = p1->next ;        }        else        {            pcurrent->next = p2 ;            pcurrent = p2 ;            p2 = p2->next ;        }    }    //p1没有移到末尾，将p1添加到新链表后面     if ( p1 != NULL )        pcurrent->next = p1 ;    //p2没有移到末尾，将p2添加到新链表后面          if ( p2 != NULL )        pcurrent->next = p2 ;    return head ;}//单链表合并，递归方式 Node * MergeRecursive(Node *head1 , Node *head2){    if ( head1 == NULL )        return head2 ;    if ( head2 == NULL)        return head1 ;    Node *head = NULL ;    if ( head1->data < head2->data )    {        head = head1 ;        head->next = MergeRecursive(head1->next,head2);    }    else    {        head = head2 ;        head->next = MergeRecursive(head1,head2->next);    }    return head ;}int main(int argc, char ** argv){    Node *head1 = CreateNode();    Node *head2 = CreateNode();    cout << "合并：" << endl;     PrintList(Merge(head1,head2));    Node *head3 = CreateNode();    Node *head4 = CreateNode();    cout << "合并：" << endl;     PrintList(MergeRecursive(head3,head4));    return 0;}

测试结果如下所示
这里写图片描述

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