C++ Program to Count rotations in sorted and rotated linked list
Given a linked list of n nodes which is first sorted, then rotated by k elements. Find the value of k.
The idea is to traverse singly linked list to check condition whether current node value is greater than value of next node. If the given condition is true, then break the loop. Otherwise increase the counter variable and increase the node by node->next. Below is the implementation of this approach.
C++
#include <bits/stdc++.h>
using namespace std;
struct Node {
int data;
struct Node* next;
};
int countRotation( struct Node* head)
{
int count = 0;
int min = head->data;
while (head != NULL) {
if (min > head->data)
break ;
count++;
head = head->next;
}
return count;
}
void push( struct Node** head, int data)
{
struct Node* newNode = new Node;
newNode->data = data;
newNode->next = (*head);
(*head) = newNode;
}
void printList( struct Node* node)
{
while (node != NULL) {
printf ( "%d " , node->data);
node = node->next;
}
}
int main()
{
struct Node* head = NULL;
push(&head, 12);
push(&head, 11);
push(&head, 8);
push(&head, 5);
push(&head, 18);
push(&head, 15);
printList(head);
cout << endl;
cout << "Linked list rotated elements: " ;
cout << countRotation(head) << endl;
return 0;
}
|
Output
15 18 5 8 11 12
Linked list rotated elements: 2
Time Complexity: O(N), where N represents the length of the linked list.
Auxiliary Space: O(1), no extra space is required, so it is a constant.
Please refer complete article on Count rotations in sorted and rotated linked list for more details!
Last Updated :
27 May, 2022
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