Answer to Question #229080 in C for Arup

Question

1. Write a C code to split the original single linked list into two sub-lists, where the first and second sub-list contains the even position nodes and odd position nodes of the original list respectively, and then join the second sub-list at the end of the first sub-list. Example: If the list contains 3->4->2->1->7->9->8, then the function needs to produce 3->2->7->8->4->1->9.

Answer 1

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


struct ListNode
{
 int data;
 struct ListNode *nextNode;
};
 


typedef struct ListNode Node;






Node* oddEvenList(Node* head)
{
        Node* temp = head;
        Node* oddNode = NULL,*odd = NULL;
        Node* even = NULL, *evenNode = NULL;


        while( temp != NULL)
        {
                if(!(temp->data%2))
                {
                        if(even == NULL)
                                even = temp;
                        else
                                evenNode->nextNode = temp;
                        evenNode = temp;
                }
                else
                {
                        if(odd == NULL)
                                odd = temp;
                        else
                                oddNode->nextNode = temp;
                        oddNode = temp;
                }
                temp = temp->nextNode;
        }
        head = odd;
        oddNode->nextNode = even;
        evenNode->nextNode = NULL;
        return head;
}
 


Node* add(Node *head, int item)
{
 Node *temp=head;
 Node *node = (Node*)malloc(sizeof(Node));
 node->data = item;
 node->nextNode = NULL;
 if(temp == NULL) 
 {
  head=node;
 }
 else if(temp->nextNode==NULL)  
 {
  temp->nextNode = node;
 }
 else
 {
  Node *temp = head;
  while(temp->nextNode != NULL) 
  {
   temp = temp->nextNode;
  }
  temp->nextNode = node; 
 }
 return head;
}
 




void printList(Node *head)
{
 Node *tempNode = head;
 while (tempNode->nextNode !=NULL)
 {
  printf("%d->",tempNode->data);
  tempNode = tempNode->nextNode;
 }
 printf("%d\n",tempNode->data);
}
 
int main()
{
 Node *node = NULL;
 int x;
 for (x=1;x<20;x++)
 {
  node = add(node,x);
 }
 printList(node);
 node=oddEvenList(node);
 printList(node);
}