ReverseLinkList.cpp

{
#include<bits/stdc++.h>
using namespace std;
/* Link list node */
struct node *reverse (struct node *head, int k);
struct node
{
    int data;
    struct node* next;
}*head;
/* UTILITY FUNCTIONS */
/* Function to push a node */
  void insert()
{
    int n,value;
    cin>>n;
    struct node *temp;
    for(int i=0;i<n;i++)
    {
        cin>>value;
        if(i==0)
        {
            head=(struct node *) malloc( sizeof(struct node) );
            head->data=value;
            head->next=NULL;
            temp=head;
            continue;
        }
        else
        {
            temp->next= (struct node *) malloc( sizeof(struct node) );
            temp=temp->next;
            temp->data=value;
            temp->next=NULL;
        }
    }
}
/* Function to print linked list */
void printList(struct node *node)
{
    while (node != NULL)
    {
        printf("%d ", node->data);
        node = node->next;
    }
printf("
");
}
/* Drier program to test above function*/
int main(void)
{
    /* Start with the empty list */
    int t,k,value,n;
     /* Created Linked list is 1->2->3->4->5->6->7->8->9 */
     cin>>t;
     while(t--)
     {
     insert();
     cin>>k;
     head = reverse(head, k);
     printList(head);
     }
     return(0);
}

}
struct node *reverseIt(struct node *head, int k){
  
    struct node *temp = head;
    struct node *prev = head;
    struct node *front = head->next;
  
    while(k-- && front!=NULL && head!=NULL){
        temp = front;
        front = temp->next;
        temp->next = prev;
        prev = temp;
    }
  
    head->next = front;
    
    return temp;
}

struct node *reverse (struct node *head, int k)
{ 
    struct node *temp = head;
    
    struct node *newHead = reverseIt(head,k-1);
    temp = head;
    head = head->next;
    
    while(head!=NULL){
        temp->next = reverseIt(head, k-1);
        temp = head;
        head = head->next;
    }

    return newHead;
}