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:

Initialize a pointer temp with the head of the linked list and a sum variable with 0.
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.
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 <bits/stdc++.h> 
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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My Personal Notes

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

C++

Java

Python3

C#

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