Replace even nodes of a doubly linked list with the elements of array

Given a doubly linked list and an array with only odd values. Both are of equal size N. The task is replace all node which have even value with the Array elements from left to right.

Examples:

Input : List = 6 9 8 7 4
Arr[] = {3, 5, 23, 17, 1}
Output : List = 3 9 5 7 23

Input : List = 9 14 7 12 8 13
Arr[] = {5, 1, 17, 21, 11, 7}
Output : List = 9 5 7 1 17 13

Approach: The idea is to traverse the nodes of the doubly linked list one by one and get the pointer of the nodes having even data then replace by the value of the array and increment the index of the array and move to the next node in the linked list.

Below is the implementation of above approach:

C++

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// C++ implementation to create
// odd 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 node
    Node* new_node = (Node*)malloc(sizeof(struct Node));
  
    // put in the data
    new_node->data = new_data;
  
    // since we are adding at the begining,
    // prev is always NULL
    new_node->prev = NULL;
  
    // link the old list off the new node
    new_node->next = (*head_ref);
  
    // change 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 make all node is odd
void makeOddNode(Node** head_ref, int A[], int n)
{
    Node* ptr = *head_ref;
    Node* next;
    int i = 0;
    // traves list till last node
    while (ptr != NULL) {
        next = ptr->next;
        // check if node is even then
        // replace it and incriment in i
        if (ptr->data % 2 == 0) {
            ptr->data = A[i];
            i++;
        }
        ptr = next;
    }
    // return sum of nodes which is divided by K
}
// function to print nodes in a
// given doubly linked list
void printList(Node* head)
{
    while (head != NULL) {
        cout << head->data << " ";
        head = head->next;
    }
}
  
// Driver program to test above
int main()
{
    // start with the empty list
    Node* head = NULL;
  
    // create the doubly linked list
    // 6 <=> 9 <=> 8 <=> 7 <=> 4
    int Arr[] = { 3, 5, 23, 17, 1 };
    push(&head, 4);
    push(&head, 7);
    push(&head, 8);
    push(&head, 9);
    push(&head, 6);
    int n = sizeof(Arr) / sizeof(Arr[0]);
    cout << "Original List: ";
    printList(head);
    cout << endl;
    makeOddNode(&head, Arr, n);
    cout << "New odd List: ";
    printList(head);
}

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Java














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// Java implementation to create  


// odd doubly linked list  


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 node  


    Node new_node = new Node();  


  


    // put in the data  


    new_node.data = new_data;  


  


    // since we are adding at the begining,  


    // prev is always null  


    new_node.prev = null;  


  


    // link the old list off the new node  


    new_node.next = (head_ref);  


  


    // change 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 make all node is odd  


static Node makeOddNode(Node head_ref, int A[], int n)  


{  


    Node ptr = head_ref;  


    Node next;  


    int i = 0;  


    // traves list till last node  


    while (ptr != null)  


    {  


        next = ptr.next;  


          


        // check if node is even then  


        // replace it and incriment in i  


        if (ptr.data % 2 == 0) 


        {  


  


            ptr.data = A[i];  


            i++;  


        }  


        ptr = next;  


    }  


      


    // return sum of nodes which is divided by K  


    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[]) 


{  


    // start with the empty list  


    Node head = null;  


  


    // create the doubly linked list  


    // 6 <=> 9 <=> 8 <=> 7 <=> 4  


    int Arr[] = { 3, 5, 23, 17, 1 };  


    head = push(head, 4);  


    head = push(head, 7);  


    head = push(head, 8);  


    head = push(head, 9);  


    head = push(head, 6);  


    int n = Arr.length;  


    System.out.print( "Original List: ");  


    printList(head);  


    System.out.println();  


    head = makeOddNode(head, Arr, n);  


    System.out.print("New odd List: ");  


    printList(head);  


}  


} 


  


// This code is contributed by Arnab Kundu 



















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Python3














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# Python3 implementation to  


# create odd doubly linked list  


  


# Node of the doubly linked list  


class Node: 


      


    def __init__(self, data): 


        self.data = data 


        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 node  


    new_node = Node(new_data)  


  


    # link the old list off the new node  


    new_node.next = head_ref  


  


    # change 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 make all node is odd  


def makeOddNode(head_ref, A, n):  


  


    ptr = head_ref  


    i = 0


      


    # traves list till last node  


    while ptr != None: 


          


        next = ptr.next


          


        # check if node is even then  


        # replace it and incriment in i  


        if ptr.data % 2 == 0:  


            ptr.data = A[i]  


            i += 1


          


        ptr = next


      


    # return sum of nodes which is divided by K  


  


# 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__":  


  


    # start with the empty list  


    head = None


  


    # create the doubly linked list  


    # 6 <=> 9 <=> 8 <=> 7 <=> 4  


    Arr = [3, 5, 23, 17, 1]  


    head = push(head, 4)  


    head = push(head, 7)  


    head = push(head, 8)  


    head = push(head, 9)  


    head = push(head, 6)  


    n = len(Arr)  


      


    print("Original List:", end = " ")  


    printList(head)  


    print() 


      


    makeOddNode(head, Arr, n)  


    print("New odd List:", end = " ")  


    printList(head)  


  


# This code is contributed by Rituraj Jain 



















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C#














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// C# implementation to create  


// odd doubly linked list 


using System; 


      


class GFG 


{ 


  


// Node of the doubly linked list  


public 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 node  


    Node new_node = new Node();  


  


    // put in the data  


    new_node.data = new_data;  


  


    // since we are adding at the begining,  


    // prev is always null  


    new_node.prev = null;  


  


    // link the old list off the new node  


    new_node.next = (head_ref);  


  


    // change 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 make all node is odd  


static Node makeOddNode(Node head_ref, int []A, int n)  


{  


    Node ptr = head_ref;  


    Node next;  


    int i = 0;  


      


    // traves list till last node  


    while (ptr != null)  


    {  


        next = ptr.next;  


          


        // check if node is even then  


        // replace it and incriment in i  


        if (ptr.data % 2 == 0) 


        {  


  


            ptr.data = A[i];  


            i++;  


        }  


        ptr = next;  


    }  


      


    // return sum of nodes which is divided by K  


    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) 


{  


    // start with the empty list  


    Node head = null;  


  


    // create the doubly linked list  


    // 6 <=> 9 <=> 8 <=> 7 <=> 4  


    int []Arr = { 3, 5, 23, 17, 1 };  


    head = push(head, 4);  


    head = push(head, 7);  


    head = push(head, 8);  


    head = push(head, 9);  


    head = push(head, 6);  


    int n = Arr.Length;  


    Console.WriteLine( "Original List: ");  


    printList(head);  


    Console.WriteLine();  


    head = makeOddNode(head, Arr, n);  


    Console.WriteLine("New odd List: ");  


    printList(head);  


}  


} 


  


// This code contributed by Rajput-Ji 



















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Output:


Original List: 6 9 8 7 4 
New odd List: 3 9 5 7 23





Time Complexity: O(N), where N is the total number of nodes.



          
          
          
          

            

    

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