Sum of all Palindrome Numbers present in a Linked list

Given a linked list with integer node values, the task is to find the sum of all Palindrome Numbers present as Node values.

Examples:

Input: 13 -> 212 -> 22 -> 44 -> 4 -> 3
Output: 285
Explanation: The sum of palindrome numbers {22, 212, 44, 4, 3} is 285

Input: 19 -> 22 -> 141
Output: 163

Approach: In order to solve this problem we are using an approach similar to calculate the Sum of all Palindromes in an Array. Iterate through all the nodes of the linked list and check if the current node value is a palindrome or not. If so, add the value and store the sum. The final sum of all such values gives the desired answer.



Below is the implementation of the above approach:

C++

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// C++ program to calculate
// the sum of all palindromic
// numbers in a linked list
  
#include <bits/stdc++.h>
using namespace std;
  
// Node of the singly
// linked list
struct Node {
    int data;
    Node* next;
};
  
// Function to insert a node at
// the beginning of the singly
// Linked List
void push(Node** head_ref, int new_data)
{
    // allocate node
    Node* new_node = (Node*)malloc(
        sizeof(struct Node));
  
    // Insert the data
    new_node->data = new_data;
  
    // Point the new Node
    // to the current head
    new_node->next = (*head_ref);
  
    // Make the new Node as
    // the new head
    (*head_ref) = new_node;
}
  
// Function to check
// if a number n is
// palindrome or not
bool isPalin(int n)
{
    int d = 0, s = 0;
    int temp = n;
    while (n > 0) {
        d = n % 10;
        s = s * 10 + d;
        n = n / 10;
    }
  
    // If n is equal to
    // the its reverse
    // it is a palindrome
    return temp == s;
}
  
// Function to calculate
// the sum of all nodes
// which are palindrome
int sumOfpal(Node* head_1)
{
    int s = 0;
    Node* ptr = head_1;
    while (ptr != NULL) {
  
        // If the value of the
        // current node is
        // a palindrome
        if (isPalin(ptr->data)) {
  
            // Add the value
            // to the sum
            s += ptr->data;
        }
        ptr = ptr->next;
    }
    return s;
}
  
// Driver Code
int main()
{
    // Create the head
    // of the linked list
    Node* head1 = NULL;
  
    // Insert nodes into
    // the linked list
    push(&head1, 13);
    push(&head1, 212);
    push(&head1, 22);
    push(&head1, 44);
    push(&head1, 4);
    push(&head1, 3);
  
    // Print the sum of all
    // palindromes
    cout << sumOfpal(head1)
         << endl;
    return 0;
}

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Java

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// Java program to calculate
// the sum of all palindromes
// in a linked list
  
import java.util.*;
  
class GFG {
  
    // Node of the singly
    // linked list
    static class Node {
        int data;
        Node next;
    };
  
    // Function to insert a node
    // at the beginning of the
    // singly Linked List
    static Node push(Node head_ref,
                     int new_data)
    {
        // Allocate node
        Node new_node = new Node();
  
        // Insert the data
        new_node.data = new_data;
  
        // Point the current Node
        // to the current head
        new_node.next = (head_ref);
  
        // Make the current node
        // as the new head
        (head_ref) = new_node;
  
        return head_ref;
    }
  
    // Function to check if
    // a number is palindrome
    static boolean isPalin(int n)
    {
        int d = 0, s = 0;
        int temp = n;
        while (n > 0) {
            d = n % 10;
            s = s * 10 + d;
            n = n / 10;
        }
        // If n is equal to its
        // reverse, it is a
        // palindrome
        return temp == s;
    }
  
    // Function to calculate sum
    // of all nodes with value
    // which is a palindrome
    static int sumOfpal(Node head_1)
    {
        int s = 0;
        Node ptr = head_1;
        while (ptr != null) {
            // If the value of the
            // current node
            // is a palindrome
            if (isPalin(ptr.data)) {
  
                // Add that value to
                // the sum
                s += ptr.data;
            }
            ptr = ptr.next;
        }
  
        // Return the sum
        return s;
    }
  
    // Driver Code
    public static void main(String args[])
    {
        // Create the head
        Node head1 = null;
  
        // Insert nodes to the
        // Linked List
        head1 = push(head1, 13);
        head1 = push(head1, 212);
        head1 = push(head1, 22);
        head1 = push(head1, 44);
        head1 = push(head1, 4);
        head1 = push(head1, 3);
  
        System.out.println(
            sumOfpal(head1));
    }
}

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Python3

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# Python3 program to 
# calculate the sum of all 
# palindromes present in 
# a Linked List
  
class Node:  
          
    def __init__(self, data):  
        self.data = data  
        self.next = next
              
# Function to insert a 
# node at the beginning  
# of the singly Linked List  
def push( head_ref, new_data) : 
      
    # Alocate node  
    new_node = Node(0)  
      
    # Insert data  
    new_node.data = new_data  
      
    # Pont to the head 
    new_node.next = (head_ref)  
      
    # Make the new Node
    # the new head
    (head_ref) = new_node 
      
    return head_ref
  
      
# Function to check if 
# a number is palindrome 
def isPalin(n) : 
      
    d = 0; s = 0
    temp = n;
    while (n > 0) : 
    
        d = n % 10
        s = s * 10 + d; 
        n = n // 10
    
    # If n is equal to its reverse, 
    # it is a palindrome 
    return s == temp; 
    
    
# Function to calculate sum of 
# all elements in a Linked List 
# which are palindrome 
def sumOfpal(head_ref1) : 
  
    s = 0
    ptr1 = head_ref1
  
    while (ptr1 != None) :
        # If the value of the 
        # current node 
        # is a palindrome
        if (isPalin(ptr1.data)) :
            
            # Add that value
            s = s + ptr1.data
  
        # Move to the next node
        ptr1 = ptr1.next
  
    # Return the final sum
    return s; 
      
# Driver code  
  
# Create the Head
head1 = None
  
# Insert nodes  
head1 = push(head1, 13)  
head1 = push(head1, 212)  
head1 = push(head1, 22)  
head1 = push(head1, 44)  
head1 = push(head1, 4)
head1 = push(head1, 3)
  
print(sumOfpal(head1))

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C#

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// C# program to calculate
// the sum of all palindromes
// in a linked list
using System;
  
class GFG {
  
// Node of the singly
// linked list
class Node
{
    public int data;
    public Node next;
};
  
// Function to insert a node
// at the beginning of the
// singly Linked List
static Node push(Node head_ref,
                 int new_data)
{
      
    // Allocate node
    Node new_node = new Node();
  
    // Insert the data
    new_node.data = new_data;
  
    // Point the current Node
    // to the current head
    new_node.next = (head_ref);
  
    // Make the current node
    // as the new head
    (head_ref) = new_node;
      
    return head_ref;
}
  
// Function to check if
// a number is palindrome
static bool isPalin(int n)
{
    int d = 0, s = 0;
    int temp = n;
      
    while (n > 0)
    {
        d = n % 10;
        s = s * 10 + d;
        n = n / 10;
    }
      
    // If n is equal to its
    // reverse, it is a
    // palindrome
    return temp == s;
}
  
// Function to calculate sum
// of all nodes with value
// which is a palindrome
static int sumOfpal(Node head_1)
{
    int s = 0;
    Node ptr = head_1;
      
    while (ptr != null)
    {
          
        // If the value of the
        // current node
        // is a palindrome
        if (isPalin(ptr.data))
        {
  
            // Add that value to
            // the sum
            s += ptr.data;
        }
        ptr = ptr.next;
    }
  
    // Return the sum
    return s;
}
  
// Driver Code
public static void Main(String []args)
{
      
    // Create the head
    Node head1 = null;
  
    // Insert nodes to the
    // Linked List
    head1 = push(head1, 13);
    head1 = push(head1, 212);
    head1 = push(head1, 22);
    head1 = push(head1, 44);
    head1 = push(head1, 4);
    head1 = push(head1, 3);
  
    Console.WriteLine(sumOfpal(head1));
}
}
  
// This code is contributed by sapnasingh4991

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Output:

285

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