# Sum of the nodes of a Circular Linked List

Given a singly Circular linked list. The task is to find the sum of nodes of the given linked list. For the above circular list, sum = 2 + 5 + 7 + 8 + 10 = 32

Examples:

```Input: 11->2->56->12
Output: Sum of Circular linked list is = 81

Input: 2-> 5 -> 7 -> 8 -> 10
Output: Sum of Circular linked list is = 32
```

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

Approach:

1. Initialize a pointer temp with the head of the linked list and a sum variable with 0.
2. Start traversing the linked list using a loop until all the nodes get traversed.

• Add the value of current node to the sum i.e. sum += temp -> data.
• Increment the pointer to the next node of linked list i.e. temp = temp -> next.
3. Return the sum.

Below is the implementation of the above approach:

## C++

 `// CPP program to find the sum of all nodes ` `// of a Circular linked list ` ` `  `#include ` `using` `namespace` `std; ` ` `  `// Structure for a node ` `struct` `Node { ` `    ``int` `data; ` `    ``struct` `Node* next; ` `}; ` ` `  `// Function to insert a node at the beginning ` `// of a Circular linked list ` `void` `push(``struct` `Node** head_ref, ``int` `data) ` `{ ` `    ``struct` `Node* ptr1 = (``struct` `Node*)``malloc``(``sizeof``(``struct` `Node)); ` `    ``struct` `Node* temp = *head_ref; ` `    ``ptr1->data = data; ` `    ``ptr1->next = *head_ref; ` ` `  `    ``// If linked list is not NULL then ` `    ``// set the next of last node ` `    ``if` `(*head_ref != NULL) { ` `        ``while` `(temp->next != *head_ref) ` `            ``temp = temp->next; ` `        ``temp->next = ptr1; ` `    ``} ` `    ``else` `        ``ptr1->next = ptr1; ``// For the first node ` ` `  `    ``*head_ref = ptr1; ` `} ` ` `  `// Function to find sum of the given ` `// Circular linked list ` `int` `sumOfList(``struct` `Node* head) ` `{ ` `    ``struct` `Node* temp = head; ` `    ``int` `sum = 0; ` `    ``if` `(head != NULL) { ` `        ``do` `{ ` `            ``temp = temp->next; ` `            ``sum += temp->data; ` `        ``} ``while` `(temp != head); ` `    ``} ` ` `  `    ``return` `sum; ` `} ` ` `  `// Driver code ` `int` `main() ` `{ ` `    ``// Initialize lists as empty ` `    ``struct` `Node* head = NULL; ` ` `  `    ``// Created linked list will be 11->2->56->12 ` `    ``push(&head, 12); ` `    ``push(&head, 56); ` `    ``push(&head, 2); ` `    ``push(&head, 11); ` ` `  `    ``cout << ``"Sum of Circular linked list is = "` `<< sumOfList(head); ` ` `  `    ``return` `0; ` `} `

## Java

 `// Java program to find the sum of ` `// all nodes of a Circular linked list  ` `import` `java.util.*; ` ` `  `class` `GFG ` `{ ` ` `  `// structure for a node  ` `static` `class` `Node  ` `{  ` `    ``int` `data;  ` `    ``Node next;  ` `};  ` ` `  `// Function to insert a node  ` `// at the beginning of a  ` `// Circular linked list  ` `static` `Node push(Node head_ref,  ` `                      ``int` `data)  ` `{  ` `    ``Node ptr1 = ``new` `Node();  ` `    ``Node temp = head_ref;  ` `    ``ptr1.data = data;  ` `    ``ptr1.next = head_ref;  ` ` `  `    ``// If linked list is not null then  ` `    ``// set the next of last node  ` `    ``if` `(head_ref != ``null``)  ` `    ``{  ` `        ``while` `(temp.next != head_ref)  ` `            ``temp = temp.next;  ` `        ``temp.next = ptr1;  ` `    ``}  ` `    ``else` `        ``ptr1.next = ptr1; ``// For the first node  ` ` `  `    ``head_ref = ptr1;  ` `     `  `    ``return` `head_ref; ` `}  ` ` `  `// Function to find sum of the  ` `// given Circular linked list  ` `static` `int` `sumOfList(Node head)  ` `{  ` `    ``Node temp = head;  ` `    ``int` `sum = ``0``;  ` `    ``if` `(head != ``null``)  ` `    ``{  ` `        ``do`  `        ``{  ` `            ``temp = temp.next;  ` `            ``sum += temp.data;  ` `        ``} ``while` `(temp != head);  ` `    ``}  ` ` `  `    ``return` `sum;  ` `}  ` ` `  `// Driver code  ` `public` `static` `void` `main(String args[]) ` `{  ` `    ``// Initialize lists as empty  ` `    ``Node head = ``null``;  ` ` `  `    ``// Created linked list will ` `    ``// be 11.2.56.12  ` `    ``head = push(head, ``12``);  ` `    ``head = push(head, ``56``);  ` `    ``head = push(head, ``2``);  ` `    ``head = push(head, ``11``);  ` ` `  `    ``System.out.println(``"Sum of Circular linked"` `+  ` `                ``" list is = "` `+ sumOfList(head));  ` `}  ` `} ` ` `  `// This code is contributed by Arnab Kundu `

## Python3

 `# Python3 program to find the sum of all nodes  ` `# of a Circular linked list  ` `import` `math ` ` `  `# class for a node ` `class` `Node: ` `    ``def` `__init__(``self``,data): ` `        ``self``.data ``=` `data ` `        ``self``.``next` `=` `None` ` `  `# Function to insert a node at the beginning  ` `# of a Circular linked list  ` `def` `push(head, data): ` `    ``if` `not` `head: ` `        ``head ``=` `Node(data) ` `        ``head.``next` `=` `head ` `        ``return` `head ` `    ``lnode ``=` `head ` ` `  `    ``# If linked list is not NULL then  ` `    ``# set the next of last node  ` `    ``while``(lnode ``and` `lnode.``next` `is` `not` `head): ` `        ``lnode ``=` `lnode.``next` `    ``ptr1 ``=` `Node(data) ``# For the first node ` `    ``ptr1.``next` `=` `head ` `    ``lnode.``next` `=` `ptr1 ` `    ``head ``=` `ptr1 ` `    ``return` `head ` ` `  `# Function to find sum of the given  ` `# Circular linked list      ` `def` `sumOfList(head): ` `    ``temp ``=` `head ` `    ``tsum ``=` `temp.data ` `    ``temp ``=` `temp.``next` `    ``while``(temp ``is` `not` `head): ` `        ``tsum ``+``=` `temp.data ` `        ``temp ``=` `temp.``next` `    ``return` `tsum ` ` `  `# Driver code  ` `if` `__name__``=``=``'__main__'``: ` `     `  `    ``# Initialize lists as empty ` `    ``head ``=` `None` ` `  `    ``# Created linked list will be 11->2->56->12  ` `    ``head ``=` `push(head, ``12``) ` `    ``head ``=` `push(head, ``56``) ` `    ``head ``=` `push(head, ``2``) ` `    ``head ``=` `push(head, ``11``) ` `    ``print``(``"Sum of circular list is = {}"` `.  ` `                  ``format``(sumOfList(head))) ` ` `  `# This code is contributed by Vikash Kumar 37 `

## C#

 `// C# program to find the sum of  ` `// all nodes of a Circular linked list  ` `using` `System; ` ` `  `class` `GFG  ` `{  ` ` `  `    ``// structure for a node  ` `    ``class` `Node  ` `    ``{  ` `        ``public` `int` `data;  ` `        ``public` `Node next;  ` `    ``};  ` ` `  `    ``// Function to insert a node  ` `    ``// at the beginning of a  ` `    ``// Circular linked list  ` `    ``static` `Node push(Node head_ref,  ` `                        ``int` `data)  ` `    ``{  ` `        ``Node ptr1 = ``new` `Node();  ` `        ``Node temp = head_ref;  ` `        ``ptr1.data = data;  ` `        ``ptr1.next = head_ref;  ` ` `  `        ``// If linked list is not null then  ` `        ``// set the next of last node  ` `        ``if` `(head_ref != ``null``)  ` `        ``{  ` `            ``while` `(temp.next != head_ref)  ` `                ``temp = temp.next;  ` `            ``temp.next = ptr1;  ` `        ``}  ` `        ``else` `            ``ptr1.next = ptr1; ``// For the first node  ` ` `  `        ``head_ref = ptr1;  ` ` `  `        ``return` `head_ref;  ` `    ``}  ` ` `  `    ``// Function to find sum of the  ` `    ``// given Circular linked list  ` `    ``static` `int` `sumOfList(Node head)  ` `    ``{  ` `        ``Node temp = head;  ` `        ``int` `sum = 0;  ` `        ``if` `(head != ``null``)  ` `        ``{  ` `            ``do` `            ``{  ` `                ``temp = temp.next;  ` `                ``sum += temp.data;  ` `            ``} ``while` `(temp != head);  ` `        ``}  ` ` `  `        ``return` `sum;  ` `    ``}  ` ` `  `    ``// Driver code  ` `    ``public` `static` `void` `Main()  ` `    ``{  ` `        ``// Initialize lists as empty  ` `        ``Node head = ``null``;  ` ` `  `        ``// Created linked list will  ` `        ``// be 11.2.56.12  ` `        ``head = push(head, 12);  ` `        ``head = push(head, 56);  ` `        ``head = push(head, 2);  ` `        ``head = push(head, 11);  ` ` `  `        ``Console.WriteLine(``"Sum of Circular linked"` `+  ` `                    ``" list is = "` `+ sumOfList(head));  ` `    ``}  ` `} ` ` `  `// This code is contributed by princiraj1992 `

Output:

```Sum of Circular linked list is = 81
```

Time Complexity: O(N) where N is the number of nodes in the linked list.
Auxiliary Space: O(1)

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