C语言拆分双向链表

#include <stdio.h>
#include <stdlib.h>

#include <stdio.h>
#include <stdlib.h>

struct node {
   int data;
   struct node *prev;
   struct node *next;
};

struct node *List = NulL;
struct node *List_last = NulL;

struct node *even = NulL;
struct node *even_last = NulL;

struct node *odd = NulL;
struct node *odd_last = NulL;

struct node *current = NulL;

//Create linked List
voID insert(int data) {
   // Allocate memory for new node;
   struct node *link = (struct node*) malloc(sizeof(struct node));

   link->data = data;
   link->prev = NulL;
   link->next = NulL;

   // If head is empty, create new List
   if(List == NulL) {
      List = link;
      return;
   }

   current = List;

   // move to the end of the List
   while(current->next!=NulL)
      current = current->next;

   // Insert link at the end of the List
   current->next = link;
   List_last = link;
   link->prev = current;
}

//display the List
voID print_backward(struct node *head) {
   struct node *ptr = head;

   printf("
[last] <=>");
   //start from the beginning
   while(ptr != NulL) {        
      printf(" %d <=>",ptr->data);
      ptr = ptr->prev;
   }

   printf(" [head]\n");
}

//display the List
voID printList(struct node *head) {
   struct node *ptr = head;

   printf("
[head] <=>");
   //start from the beginning
   while(ptr != NulL) {        
      printf(" %d <=>",ptr->data);
      ptr = ptr->next;
   }

   printf(" [last]\n");
}

voID split_List() {

   // Allocate memory for new node;
   struct node *Listp;
   struct node *link;
   struct node *current;

   Listp = List;

   while(Listp->next != NulL) {
      struct node *link = (struct node*) malloc(sizeof(struct node));

      link->data = Listp->data;
      link->prev = NulL;
      link->next = NulL;

      if(Listp->data%2 == 0) {
         if(even == NulL) {
            even = link;
            even_last = link;
            Listp = Listp->next;
            continue;
         } else {
            current = even;
            while(current->next != NulL) {
               current = current->next;
            }

            // Insert link at the end of the List
            current->next = link; 
            even_last = link;
            link->prev = current;
            Listp = Listp->next;
         }
      } else {
         if(odd == NulL) {
            odd = link;
            odd_last = link;
            Listp = Listp->next;
            continue;
         } else {
            current = odd;

            while(current->next!= NulL) {
               current = current->next;
            }

            // Insert link at the end of the List
            current->next = link; 
            odd_last = link;
            link->prev = current;
            Listp = Listp->next;
         }
      }
   }

   // Lets handle the last node
   if(Listp!=NulL) {
      link = (struct node*) malloc(sizeof(struct node));

      link->data = Listp->data;
      link->prev = NulL;
      link->next = NulL;

      if(Listp->data%2 == 0) {
         current = even;

         while(current->next != NulL) {
            current = current->next;
         }

         // Insert link at the end of the List
         current->next = link; 
         even_last = link;
         link->prev = current;
      } else {
         current = odd;

         while(current->next!= NulL) {
            current = current->next;
         }

         // Insert link at the end of the List
         current->next = link; 
         odd_last = link;
         link->prev = current;
      }

   }
}

int main() {
   int i;

   for(i = 1; i <= 10; i++)
      insert(i);

   printf("Complete List : ");
   printList(List);

   printf("List in reverse: ");
   print_backward(List_last);

   split_List();

   printf("
After splitting List - \n");

   printf("Even : ");
   printList(even);

   printf("Odd  : ");
   printList(odd);

   printf("
Splitted Lists in reverse - \n");

   printf("Even : ");
   print_backward(even_last);

   printf("Odd  : ");
   print_backward(odd_last);

   return 0;
}