链表知识点（十一）【合并链表之后仍然有序】

方法1：递归实现：

Node * MergeList(Node *Head1,Node *Head2)

{

       if(Head1 == NULL)

       {

              return Head2;

       }

       if(Head2 == NULL)

       {

              return Head1;

       }

    Node *Head =NULL;

       if(Head1->data > Head2->data)

       {

              Head =Head2;

              Head->next= MergeList(Head1,Head2->next);

       }

       else

       {

              Head =Head1;

              Head->next= MergeList(Head1->next,Head2);

       }

       return Head;

}

方法2：递归实现：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。(保留所有结点，即便大小相同）

Node * Merge(Node *head1 , Node *head2)

{

         Node *head =NULL ;

         Node *p1 =NULL;

         Node *p2 =NULL;

    Node *pcurrent =head;

 

         if ( head1 == NULL)

         {

                   return head2 ;

         }

         if ( head2 == NULL)

         {

                   return head1 ;

         }

         if ( head1->data < head2->data )

         {

                   head= head1 ;

                   p1 =head1->next;

                   p2 =head2 ;

         }

         else

         {

                   head= head2 ;

                   p2 =head2->next ;

                   p1 =head1 ;

         }

         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 ;

                   }

         }

         if ( p1 != NULL )

         {

            pcurrent->next = p1 ;

         }

         if ( p2 != NULL )

         {

            pcurrent->next = p2 ;

         }

         return head ;

}