# Reverse a circular linked list

Given a circular linked list of size n. The problem is to reverse the given circular linked list by changing links between the nodes.

Examples:
INPUT: OUTPUT: ## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Approach: The approach is same as followed in reversing a singly linked list. Only here we have to make one more adjustment by linking the last node of the reversed list to the first node.

## C++

 `// C++ implementation to reverse ` `// a circular linked list ` `#include ` ` `  `using` `namespace` `std; ` ` `  `// Linked list node ` `struct` `Node { ` `    ``int` `data; ` `    ``Node* next; ` `}; ` ` `  `// function to get a new node ` `Node* getNode(``int` `data) ` `{ ` `    ``// allocate memory for node ` `    ``Node* newNode = ``new` `Node; ` ` `  `    ``// put in the data ` `    ``newNode->data = data; ` `    ``newNode->next = NULL; ` `    ``return` `newNode; ` `} ` ` `  `// Function to reverse the circular linked list ` `void` `reverse(Node** head_ref) ` `{ ` `    ``// if list is empty ` `    ``if` `(*head_ref == NULL) ` `        ``return``; ` ` `  `    ``// reverse procedure same as reversing a ` `    ``// singly linked list ` `    ``Node* prev = NULL; ` `    ``Node* current = *head_ref; ` `    ``Node* next; ` `    ``do` `{ ` `        ``next = current->next; ` `        ``current->next = prev; ` `        ``prev = current; ` `        ``current = next; ` `    ``} ``while` `(current != (*head_ref)); ` ` `  `    ``// adjutsing the links so as to make the ` `    ``// last node point to the first node ` `    ``(*head_ref)->next = prev; ` `    ``*head_ref = prev; ` `} ` ` `  `// Function to print circular linked list ` `void` `printList(Node* head) ` `{ ` `    ``if` `(head == NULL) ` `        ``return``; ` ` `  `    ``Node* temp = head; ` `    ``do` `{ ` `        ``cout << temp->data << ``" "``; ` `        ``temp = temp->next; ` `    ``} ``while` `(temp != head); ` `} ` ` `  `// Driver program to test above ` `int` `main() ` `{ ` `    ``// Create a circular linked list ` `    ``// 1->2->3->4->1 ` `    ``Node* head = getNode(1); ` `    ``head->next = getNode(2); ` `    ``head->next->next = getNode(3); ` `    ``head->next->next->next = getNode(4); ` `    ``head->next->next->next->next = head; ` ` `  `    ``cout << ``"Given circular linked list: "``; ` `    ``printList(head); ` ` `  `    ``reverse(&head); ` ` `  `    ``cout << ``"\nReversed circular linked list: "``; ` `    ``printList(head); ` ` `  `    ``return` `0; ` `} `

## Java

 `// Java implementation to reverse  ` `// a circular linked list  ` `class` `GFG ` `{ ` ` `  `// Linked list node  ` `static` `class` `Node ` `{  ` `    ``int` `data;  ` `    ``Node next;  ` `};  ` ` `  `// function to get a new node  ` `static` `Node getNode(``int` `data)  ` `{  ` `    ``// allocate memory for node  ` `    ``Node newNode = ``new` `Node();  ` ` `  `    ``// put in the data  ` `    ``newNode.data = data;  ` `    ``newNode.next = ``null``;  ` `    ``return` `newNode;  ` `}  ` ` `  `// Function to reverse the circular linked list  ` `static` `Node reverse(Node head_ref)  ` `{  ` `    ``// if list is empty  ` `    ``if` `(head_ref == ``null``)  ` `        ``return` `null``;  ` ` `  `    ``// reverse procedure same as reversing a  ` `    ``// singly linked list  ` `    ``Node prev = ``null``;  ` `    ``Node current = head_ref;  ` `    ``Node next;  ` `    ``do`  `    ``{  ` `        ``next = current.next;  ` `        ``current.next = prev;  ` `        ``prev = current;  ` `        ``current = next;  ` `    ``} ``while` `(current != (head_ref));  ` ` `  `    ``// adjutsing the links so as to make the  ` `    ``// last node point to the first node  ` `    ``(head_ref).next = prev;  ` `    ``head_ref = prev;  ` `    ``return` `head_ref; ` `}  ` ` `  `// Function to print circular linked list  ` `static` `void` `printList(Node head)  ` `{  ` `    ``if` `(head == ``null``)  ` `        ``return``;  ` ` `  `    ``Node temp = head;  ` `    ``do` `    ``{  ` `        ``System.out.print( temp.data + ``" "``);  ` `        ``temp = temp.next;  ` `    ``} ``while` `(temp != head);  ` `}  ` ` `  `// Driver code  ` `public` `static` `void` `main(String args[]) ` `{  ` `    ``// Create a circular linked list  ` `    ``// 1.2.3.4.1  ` `    ``Node head = getNode(``1``);  ` `    ``head.next = getNode(``2``);  ` `    ``head.next.next = getNode(``3``);  ` `    ``head.next.next.next = getNode(``4``);  ` `    ``head.next.next.next.next = head;  ` ` `  `    ``System.out.print(``"Given circular linked list: "``);  ` `    ``printList(head);  ` ` `  `    ``head = reverse(head);  ` ` `  `    ``System.out.print(``"\nReversed circular linked list: "``);  ` `    ``printList(head);  ` ` `  `}  ` `} ` ` `  `// This code is contributed by Arnab Kundu `

## Python3

 `# Python3 implementation to reverse ` `# a circular linked list ` `import` `math ` ` `  `# Linked list node ` `class` `Node:  ` `    ``def` `__init__(``self``, data):  ` `        ``self``.data ``=` `data  ` `        ``self``.``next` `=` `None` ` `  `# function to get a new node ` `def` `getNode(data): ` `     `  `    ``# allocate memory for node ` `    ``newNode ``=` `Node(data) ` ` `  `    ``# put in the data ` `    ``newNode.data ``=` `data ` `    ``newNode.``next` `=` `None` `    ``return` `newNode ` ` `  `# Function to reverse the  ` `# circular linked list ` `def` `reverse(head_ref): ` `     `  `    ``# if list is empty ` `    ``if` `(head_ref ``=``=` `None``): ` `        ``return` `None` ` `  `    ``# reverse procedure same as  ` `    ``# reversing a singly linked list ` `    ``prev ``=` `None` `    ``current ``=` `head_ref ` `     `  `    ``next` `=` `current.``next` `    ``current.``next` `=` `prev ` `    ``prev ``=` `current ` `    ``current ``=` `next` `    ``while` `(current !``=` `head_ref): ` `        ``next` `=` `current.``next` `        ``current.``next` `=` `prev ` `        ``prev ``=` `current ` `        ``current ``=` `next` ` `  `    ``# adjutsing the links so as to make the ` `    ``# last node po to the first node ` `    ``head_ref.``next` `=` `prev ` `    ``head_ref ``=` `prev ` `    ``return` `head_ref ` ` `  `# Function to print circular linked list ` `def` `prList(head): ` `    ``if` `(head ``=``=` `None``): ` `        ``return` ` `  `    ``temp ``=` `head ` `     `  `    ``print``(temp.data, end ``=` `" "``) ` `    ``temp ``=` `temp.``next` `    ``while` `(temp !``=` `head): ` `        ``print``(temp.data, end ``=` `" "``) ` `        ``temp ``=` `temp.``next` ` `  `# Driver Code ` `if` `__name__``=``=``'__main__'``:  ` `     `  `    ``# Create a circular linked list ` `    ``# 1.2.3.4.1 ` `    ``head ``=` `getNode(``1``) ` `    ``head.``next` `=` `getNode(``2``) ` `    ``head.``next``.``next` `=` `getNode(``3``) ` `    ``head.``next``.``next``.``next` `=` `getNode(``4``) ` `    ``head.``next``.``next``.``next``.``next` `=` `head ` ` `  `    ``print``(``"Given circular linked list: "``,  ` `                                ``end ``=` `"") ` `    ``prList(head) ` ` `  `    ``head ``=` `reverse(head) ` ` `  `    ``print``(``"\nReversed circular linked list: "``,  ` `                                     ``end ``=` `"") ` `    ``prList(head) ` ` `  `# This code is contributed by Srathore `

## C#

 `// C# implementation to reverse  ` `// a circular linked list  ` `using` `System; ` ` `  `class` `GFG  ` `{  ` ` `  `    ``// Linked list node  ` `    ``public` `class` `Node  ` `    ``{  ` `        ``public` `int` `data;  ` `        ``public` `Node next;  ` `    ``};  ` `     `  `    ``// function to get a new node  ` `    ``static` `Node getNode(``int` `data)  ` `    ``{  ` `        ``// allocate memory for node  ` `        ``Node newNode = ``new` `Node();  ` `     `  `        ``// put in the data  ` `        ``newNode.data = data;  ` `        ``newNode.next = ``null``;  ` `        ``return` `newNode;  ` `    ``}  ` `     `  `    ``// Function to reverse the circular linked list  ` `    ``static` `Node reverse(Node head_ref)  ` `    ``{  ` `        ``// if list is empty  ` `        ``if` `(head_ref == ``null``)  ` `            ``return` `null``;  ` `     `  `        ``// reverse procedure same as reversing a  ` `        ``// singly linked list  ` `        ``Node prev = ``null``;  ` `        ``Node current = head_ref;  ` `        ``Node next;  ` `        ``do` `        ``{  ` `            ``next = current.next;  ` `            ``current.next = prev;  ` `            ``prev = current;  ` `            ``current = next;  ` `        ``} ``while` `(current != (head_ref));  ` `     `  `        ``// adjutsing the links so as to make the  ` `        ``// last node point to the first node  ` `        ``(head_ref).next = prev;  ` `        ``head_ref = prev;  ` `        ``return` `head_ref;  ` `    ``}  ` `     `  `    ``// Function to print circular linked list  ` `    ``static` `void` `printList(Node head)  ` `    ``{  ` `        ``if` `(head == ``null``)  ` `            ``return``;  ` `     `  `        ``Node temp = head;  ` `        ``do` `        ``{  ` `            ``Console.Write( temp.data + ``" "``);  ` `            ``temp = temp.next;  ` `        ``} ``while` `(temp != head);  ` `    ``}  ` `     `  `    ``// Driver code  ` `    ``public` `static` `void` `Main(String []args)  ` `    ``{  ` `        ``// Create a circular linked list  ` `        ``// 1.2.3.4.1  ` `        ``Node head = getNode(1);  ` `        ``head.next = getNode(2);  ` `        ``head.next.next = getNode(3);  ` `        ``head.next.next.next = getNode(4);  ` `        ``head.next.next.next.next = head;  ` `     `  `        ``Console.Write(``"Given circular linked list: "``);  ` `        ``printList(head);  ` `     `  `        ``head = reverse(head);  ` `     `  `        ``Console.Write(``"\nReversed circular linked list: "``);  ` `        ``printList(head);  ` `     `  `    ``}  ` `}  ` ` `  `// This code contributed by Rajput-Ji `

Output:

```Given circular linked list: 1 2 3 4
Reversed circular linked list: 4 3 2 1
```

Time Complexity: O(n)

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