Remove all the Even Digit Sum Nodes from a Doubly Linked List
Given a Doubly linked list containing N nodes, the task is to remove all the nodes from the list which contains elements whose digit sum is even.
Examples:
Input: DLL = 18 <=> 15 <=> 8 <=> 9 <=> 14
Output: 18 <=> 9 <=> 14
Explanation:
The linked list contains :
18 -> 1 + 8 = 9
15 -> 1 + 5 = 6
8 -> 8
9 -> 9
14 -> 1 + 4 = 5
Here, digit sum for nodes containing 15 and 8 are even.
Hence, these nodes have been deleted.Input: DLL = 5 <=> 3 <=> 4 <=> 2 <=> 9
Output: 5 <=> 3 <=> 9
Explanation:
The linked list contains two digit sum values 4 and 2.
Hence, these nodes have been deleted.
Approach:
A simple approach is to traverse the nodes of the doubly linked list one by one and for each node first, find the digit sum for the value present in the node by iterating through each digit and then finally remove the nodes whose digit sum is even.
Below is the implementation of the above approach:
C++
// C++ implementation to remove all // the Even Digit Sum Nodes from a // doubly linked list #include <bits/stdc++.h> using namespace std; // Node of the doubly linked list struct Node { int data; Node *prev, *next; }; // Function to insert a node at the beginning // of the Doubly Linked List void push(Node** head_ref, int new_data) { // Allocate the node Node* new_node = (Node*) malloc ( sizeof ( struct Node)); // Insert the data new_node->data = new_data; // Since we are adding at the beginning, // prev is always NULL new_node->prev = NULL; // Link the old list off the new node new_node->next = (*head_ref); // Change the prev of head node to new node if ((*head_ref) != NULL) (*head_ref)->prev = new_node; // Move the head to point to the new node (*head_ref) = new_node; } // Function to find the digit sum // for a number int digitSum( int num) { int sum = 0; while (num) { sum += (num % 10); num /= 10; } return sum; } // Function to delete a node // in a Doubly Linked List. // head_ref --> pointer to head node pointer. // del --> pointer to node to be deleted void deleteNode(Node** head_ref, Node* del) { // Base case if (*head_ref == NULL || del == NULL) return ; // If the node to be deleted is head node if (*head_ref == del) *head_ref = del->next; // Change next only if node to be // deleted is not the last node if (del->next != NULL) del->next->prev = del->prev; // Change prev only if node to be // deleted is not the first node if (del->prev != NULL) del->prev->next = del->next; // Finally, free the memory // occupied by del free (del); return ; } // Function to to remove all // the Even Digit Sum Nodes from a // doubly linked list void deleteEvenDigitSumNodes(Node** head_ref) { Node* ptr = *head_ref; Node* next; // Iterating through the linked list while (ptr != NULL) { next = ptr->next; // If node's data's digit sum // is even if (!(digitSum(ptr->data) & 1)) deleteNode(head_ref, ptr); ptr = next; } } // Function to print nodes in a // given doubly linked list void printList(Node* head) { while (head != NULL) { cout << head->data << " " ; head = head->next; } } // Driver Code int main() { Node* head = NULL; // Create the doubly linked list // 18 <-> 15 <-> 8 <-> 9 <-> 14 push(&head, 14); push(&head, 9); push(&head, 8); push(&head, 15); push(&head, 18); cout << "Original List: " ; printList(head); deleteEvenDigitSumNodes(&head); cout << "\nModified List: " ; printList(head); } |
Java
// Java implementation to // remove all the Even // Digit Sum Nodes from a // doubly linked list import java.util.*; class GFG{ // Node of the doubly // linked list static class Node { int data; Node prev, next; }; // Function to insert a node // at the beginning of the // Doubly Linked List static Node push(Node head_ref, int new_data) { // Allocate the node Node new_node = new Node(); // Insert the data new_node.data = new_data; // Since we are adding // at the beginning, // prev is always null new_node.prev = null ; // Link the old list // off the new node new_node.next = head_ref; // Change the prev of // head node to new node if (head_ref != null ) head_ref.prev = new_node; // Move the head to point // to the new node head_ref = new_node; return head_ref; } // Function to find the digit sum // for a number static int digitSum( int num) { int sum = 0 ; while (num > 0 ) { sum += (num % 10 ); num /= 10 ; } return sum; } // Function to delete a node // in a Doubly Linked List. // head_ref -. pointer to head node pointer. // del -. pointer to node to be deleted static Node deleteNode(Node head_ref, Node del) { // Base case if (head_ref == null || del == null ) return head_ref; // If the node to be // deleted is head node if (head_ref == del) head_ref = del.next; // Change next only if node to be // deleted is not the last node if (del.next != null ) del.next.prev = del.prev; // Change prev only if node to be // deleted is not the first node if (del.prev != null ) del.prev.next = del.next; // Finally, free the memory // occupied by del del = null ; return head_ref; } // Function to to remove all // the Even Digit Sum Nodes from a // doubly linked list static Node deleteEvenDigitSumNodes(Node head_ref) { Node ptr = head_ref; Node next; // Iterating through the linked list while (ptr != null ) { next = ptr.next; // If node's data's digit sum // is even if (!(digitSum(ptr.data) % 2 == 1 )) head_ref = deleteNode(head_ref, ptr); ptr = next; } return head_ref; } // Function to print nodes in a // given doubly linked list static void printList(Node head) { while (head != null ) { System.out.print(head.data + " " ); head = head.next; } } // Driver Code public static void main(String[] args) { Node head = null ; // Create the doubly linked list // 18 <. 15 <. 8 <. 9 <. 14 head = push(head, 14 ); head = push(head, 9 ); head = push(head, 8 ); head = push(head, 15 ); head = push(head, 18 ); System.out.print( "Original List: " ); printList(head); head = deleteEvenDigitSumNodes(head); System.out.print( "\nModified List: " ); printList(head); } } // This code is contributed by shikhasingrajput |
Python3
# Python3 implementation to remove all # the Even Digit Sum Nodes from a # doubly linked list # Node of the doubly linked list class Node(): def __init__( self ): self .data = 0 self .prev = None self . next = None # Function to insert a node at the # beginning of the Doubly Linked List def push(head_ref, new_data): # Allocate the node new_node = Node() # Insert the data new_node.data = new_data # Since we are adding at the beginning, # prev is always NULL new_node.prev = None # Link the old list off the new node new_node. next = head_ref # Change the prev of head node to new node if ((head_ref) ! = None ): (head_ref).prev = new_node # Move the head to point to the new node (head_ref) = new_node return head_ref # Function to find the digit sum # for a number def digitSum(num): sum = 0 while (num ! = 0 ): sum + = (num % 10 ) num / / = 10 return sum # Function to delete a node # in a Doubly Linked List. # head_ref --> pointer to head node pointer. # delete --> pointer to node to be deleted def deleteNode(head_ref, delete): # Base case if (head_ref = = None or delete = = None ): return # If the node to be deleted is head node if (head_ref = = delete): head_ref = delete. next # Change next only if node to be # deleted is not the last node if (delete. next ! = None ): delete. next .prev = delete.prev # Change prev only if node to be # deleted is not the first node if (delete.prev ! = None ): delete.prev. next = delete. next # Finally, free the memory # occupied by delete del delete return # Function to to remove all # the Even Digit Sum Nodes from a # doubly linked list def deleteEvenDigitSumNodes(head_ref): ptr = head_ref next = None # Iterating through the linked list while (ptr ! = None ): next = ptr. next # If node's data's digit sum # is even if ( not (digitSum(ptr.data) & 1 )): deleteNode(head_ref, ptr) ptr = next return head_ref # Function to print nodes in a # given doubly linked list def printList(head): while (head ! = None ): print (head.data, end = " " ) head = head. next # Driver code if __name__ = = "__main__" : head = None # Create the doubly linked list # 18 <-> 15 <-> 8 <-> 9 <-> 14 head = push(head, 14 ) head = push(head, 9 ) head = push(head, 8 ) head = push(head, 15 ) head = push(head, 18 ) print ( "Original List:" , end = " " ) printList(head) head = deleteEvenDigitSumNodes(head) print ( "\nModified List: " , end = " " ) printList(head) # This code is contributed by rutvik_56 |
C#
// C# implementation to // remove all the Even // Digit Sum Nodes from a // doubly linked list using System; class GFG{ // Node of the doubly // linked list class Node { public int data; public Node prev, next; }; // Function to insert a node // at the beginning of the // Doubly Linked List static Node push(Node head_ref, int new_data) { // Allocate the node Node new_node = new Node(); // Insert the data new_node.data = new_data; // Since we are adding // at the beginning, // prev is always null new_node.prev = null ; // Link the old list // off the new node new_node.next = head_ref; // Change the prev of // head node to new node if (head_ref != null ) head_ref.prev = new_node; // Move the head to point // to the new node head_ref = new_node; return head_ref; } // Function to find the digit sum // for a number static int digitSum( int num) { int sum = 0; while (num > 0) { sum += (num % 10); num /= 10; } return sum; } // Function to delete a node // in a Doubly Linked List. // head_ref -. pointer to head node pointer. // del -. pointer to node to be deleted static Node deleteNode(Node head_ref, Node del) { // Base case if (head_ref == null || del == null ) return head_ref; // If the node to be // deleted is head node if (head_ref == del) head_ref = del.next; // Change next only if node to be // deleted is not the last node if (del.next != null ) del.next.prev = del.prev; // Change prev only if node to be // deleted is not the first node if (del.prev != null ) del.prev.next = del.next; // Finally, free the memory // occupied by del del = null ; return head_ref; } // Function to to remove all // the Even Digit Sum Nodes from a // doubly linked list static Node deleteEvenDigitSumNodes(Node head_ref) { Node ptr = head_ref; Node next; // Iterating through the linked list while (ptr != null ) { next = ptr.next; // If node's data's digit sum // is even if (!(digitSum(ptr.data) % 2 == 1)) head_ref = deleteNode(head_ref, ptr); ptr = next; } return head_ref; } // Function to print nodes in a // given doubly linked list static void printList(Node head) { while (head != null ) { Console.Write(head.data + " " ); head = head.next; } } // Driver Code public static void Main(String[] args) { Node head = null ; // Create the doubly linked list // 18 <. 15 <. 8 <. 9 <. 14 head = push(head, 14); head = push(head, 9); head = push(head, 8); head = push(head, 15); head = push(head, 18); Console.Write( "Original List: " ); printList(head); head = deleteEvenDigitSumNodes(head); Console.Write( "\nModified List: " ); printList(head); } } // This code is contributed by shikhasingrajput |
Javascript
<script> // Javascript implementation to remove all // the Even Digit Sum Nodes from a // doubly linked list // Node of the doubly linked list class Node { constructor() { this .data = 0; this .prev = null ; this .next = null ; } }; // Function to insert a node at the beginning // of the Doubly Linked List function push(head_ref, new_data) { // Allocate the node var new_node = new Node(); // Insert the data new_node.data = new_data; // Since we are adding at the beginning, // prev is always null new_node.prev = null ; // Link the old list off the new node new_node.next = (head_ref); // Change the prev of head node to new node if ((head_ref) != null ) (head_ref).prev = new_node; // Move the head to point to the new node (head_ref) = new_node; return head_ref; } // Function to find the digit sum // for a number function digitSum(num) { var sum = 0; while (num) { sum += (num % 10); num = parseInt(num/10); } return sum; } // Function to delete a node // in a Doubly Linked List. // head_ref -. pointer to head node pointer. // del -. pointer to node to be deleted function deleteNode(head_ref, del) { // Base case if (head_ref == null || del == null ) return ; // If the node to be deleted is head node if (head_ref == del) head_ref = del.next; // Change next only if node to be // deleted is not the last node if (del.next != null ) del.next.prev = del.prev; // Change prev only if node to be // deleted is not the first node if (del.prev != null ) del.prev.next = del.next; return ; } // Function to to remove all // the Even Digit Sum Nodes from a // doubly linked list function deleteEvenDigitSumNodes(head_ref) { var ptr = head_ref; var next; // Iterating through the linked list while (ptr != null ) { next = ptr.next; // If node's data's digit sum // is even if (!(digitSum(ptr.data) & 1)) deleteNode(head_ref, ptr); ptr = next; } return head_ref; } // Function to print nodes in a // given doubly linked list function printList(head) { while (head != null ) { document.write( head.data + " " ); head = head.next; } } // Driver Code var head = null ; // Create the doubly linked list // 18 <. 15 <. 8 <. 9 <. 14 head = push(head, 14); head = push(head, 9); head = push(head, 8); head = push(head, 15); head = push(head, 18); document.write( "Original List: " ); printList(head); head = deleteEvenDigitSumNodes(head); document.write( "<br>Modified List: " ); printList(head); // This code is contributed by noob2000. </script> |
Original List: 18 15 8 9 14 Modified List: 18 9 14
Time Complexity: O(N), where N is the total number of nodes.