链表合并

#include <stdio.h>
#include <iostream>
using namespace std;

//已知有两个有序链表head1，head1，将它们合并成一个新的有序链表
typedef struct Node
{
int data;
struct Node *next;
}NODE;

NODE* Merge(NODE *head1,NODE *head2)
{
//若链表head1为空,返回head2
if(head1==NULL)
{
return head2;
}
//若链表head2为空，返回head1
if(head2==NULL)
{
return head1;
}
NODE *head = NULL;
NODE *p1 = NULL;
NODE *p2 = NULL;
//将数据最小的链表头给head，引入p1,p2进行指针的向后移动
if(head1->data <= head2->data)
{
head = head1;
p1 = head1->next;
p2 = head2;
}
else
{
head = head2;
p1 = head1;
p2 = head2->next;
}
NODE *pc = head; //current node
while(p1!=NULL && p2!=NULL)
{
if(p1->data <= p2->data)
{
pc->next=p1;
pc  = p1;
p1 = p1->next;
}
else
{
pc->next = p2;
pc = p2;
p2 = p2->next;
}
}
if(p1!=NULL)
{
pc->next = p1;
}
else if(p2!=NULL)
{
pc->next=p2;
}
return head;
}
//链表的创建
NODE* Create(NODE p[],int n)
{
NODE *head = &p[0];
for(int i=0;i<n-1;i++)
{
p[i].next = &p[i+1];
}
p[n-1].next = NULL;
return head;
}
//链表的输出
void output(NODE *head)
{
NODE *p = head;
int i = 0;
while(p!=NULL)
{
printf("%d\t",p->data);
p = p->next;
if(++i%5==0)
{
printf("\n");
}
}
}

int main()
{

NODE a[10] = {{1},{3},{4},{6},{8},{12},{15},{17},{19},{23}};
NODE b[5] ={{4},{5},{7},{10},{18}};
NODE *head1 = Create(a,10);
NODE *head2 = Create(b,5);
printf("原始链表head1是：\n");
output(head1);
printf("\n原始链表head2是：\n");
output(head2);
NODE *head =Merge(head1,head2);
printf("\n合并后的链表head是：\n");
output(head);
system("pause");
return 0;
}

//递归
NODE* MergeRec(NODE *head1,NODE *head2)
{
//若链表head1为空,返回head2
if(head1==NULL)
{
return head2;
}
//若链表head2为空，返回head1
if(head2==NULL)
{
return head1;
}
NODE *head = NULL;
if(head1->data<=head2->data)
{
head = head1;
head->next = MergeRec(head1->next,head2);
}
else
{
head = head2;
head->next = MergeRec(head1,head2->next);
}
return head;
}