C示例拆分双向链表

#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("\n[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("\n[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("\nAfter splitting list - \n");



   printf("Even : ");

   printList(even);



   printf("Odd  : ");

   printList(odd);



   printf("\nSplitted lists in reverse - \n");



   printf("Even : ");

   print_backward(even_last);



   printf("Odd  : ");

   print_backward(odd_last);



   return 0;

}