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Point arbit pointer to greatest value right side node in a linked list

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Given singly linked list with every node having an additional “arbitrary” pointer that currently points to NULL. We need to make the “arbitrary” pointer to the greatest value node in a linked list on its right side.

listwithArbit1

A Simple Solution is to traverse all nodes one by one. For every node, find the node which has the greatest value on the right side and change the next pointer. The Time Complexity of this solution is O(n2).

An Efficient Solution can work in O(n) time. Below are the steps.  

  1. Reverse the given linked list.
  2. Start traversing the linked list and store the maximum value node encountered so far. Make arbit of every node to point to max. If the data in the current node is more than the max node so far, update max.
  3. Reverse modified linked list and return head.

Following is the implementation of the above steps.  

C++




// C++ program to point arbit pointers to highest
// value on its right
#include<bits/stdc++.h>
using namespace std;
 
/* Link list node */
struct Node
{
    int data;
    Node* next, *arbit;
};
 
/* Function to reverse the linked list */
Node* reverse(Node *head)
{
    Node *prev = NULL, *current = head, *next;
    while (current != NULL)
    {
        next  = current->next;
        current->next = prev;
        prev = current;
        current = next;
    }
    return prev;
}
 
// This function populates arbit pointer in every
// node to the greatest value to its right.
Node* populateArbit(Node *head)
{
    // Reverse given linked list
    head = reverse(head);
 
    // Initialize pointer to maximum value node
    Node *max = head;
 
    // Traverse the reversed list
    Node *temp = head->next;
    while (temp != NULL)
    {
        // Connect max through arbit pointer
        temp->arbit = max;
 
        // Update max if required
        if (max->data < temp->data)
            max = temp;
 
        // Move ahead in reversed list
        temp = temp->next;
    }
 
    // Reverse modified linked list and return
    // head.
    return reverse(head);
}
 
// Utility function to print result linked list
void printNextArbitPointers(Node *node)
{
    printf("Node\tNext Pointer\tArbit Pointer\n");
    while (node!=NULL)
    {
        cout << node->data << "\t\t";
 
        if (node->next)
            cout << node->next->data << "\t\t";
        else cout << "NULL" << "\t\t";
 
        if (node->arbit)
            cout << node->arbit->data;
        else cout << "NULL";
 
        cout << endl;
        node = node->next;
    }
}
 
/* Function to create a new node with given data */
Node *newNode(int data)
{
    Node *new_node = new Node;
    new_node->data = data;
    new_node->next = NULL;
    return new_node;
}
 
/* Driver program to test above functions*/
int main()
{
    Node *head = newNode(5);
    head->next = newNode(10);
    head->next->next = newNode(2);
    head->next->next->next = newNode(3);
 
    head = populateArbit(head);
 
    printf("Resultant Linked List is: \n");
    printNextArbitPointers(head);
 
    return 0;
}


Java




// Java program to point arbit pointers to highest
// value on its right
class GfG
{
 
/* Link list node */
static class Node
{
    int data;
    Node next, arbit;
}
 
/* Function to reverse the linked list */
static Node reverse(Node head)
{
    Node prev = null, current = head, next = null;
    while (current != null)
    {
        next = current.next;
        current.next = prev;
        prev = current;
        current = next;
    }
    return prev;
}
 
// This function populates arbit pointer in every
// node to the greatest value to its right.
static Node populateArbit(Node head)
{
    // Reverse given linked list
    head = reverse(head);
 
    // Initialize pointer to maximum value node
    Node max = head;
 
    // Traverse the reversed list
    Node temp = head.next;
    while (temp != null)
    {
        // Connect max through arbit pointer
        temp.arbit = max;
 
        // Update max if required
        if (max.data < temp.data)
            max = temp;
 
        // Move ahead in reversed list
        temp = temp.next;
    }
 
    // Reverse modified linked list and return
    // head.
    return reverse(head);
}
 
// Utility function to print result linked list
static void printNextArbitPointers(Node node)
{
    System.out.println("Node\tNext Pointer\tArbit Pointer");
    while (node != null)
    {
        System.out.print(node.data + "\t\t");
 
        if (node.next != null)
            System.out.print(node.next.data + "\t\t");
        else
            System.out.print("NULL" +"\t\t");
 
        if (node.arbit != null)
            System.out.print(node.arbit.data);
        else
            System.out.print("NULL");
 
        System.out.println();
        node = node.next;
    }
}
 
/* Function to create a new node with given data */
static Node newNode(int data)
{
    Node new_node = new Node();
    new_node.data = data;
    new_node.next = null;
    return new_node;
}
 
/* Driver code*/
public static void main(String[] args)
{
    Node head = newNode(5);
    head.next = newNode(10);
    head.next.next = newNode(2);
    head.next.next.next = newNode(3);
 
    head = populateArbit(head);
 
    System.out.println("Resultant Linked List is: ");
    printNextArbitPointers(head);
 
}
}
 
// This code is contributed by Prerna Saini.


Python




# Python Program to point arbit pointers to highest
# value on its right
 
# Node class
class Node:
 
    # Constructor to initialize the node object
    def __init__(self, data):
        self.data = data
        self.next = None
        self.arbit = None
 
# Function to reverse the linked list
def reverse(head):
 
    prev = None
    current = head
    next = None
    while (current != None):
     
        next = current.next
        current.next = prev
        prev = current
        current = next
     
    return prev
 
# This function populates arbit pointer in every
# node to the greatest value to its right.
def populateArbit(head):
 
    # Reverse given linked list
    head = reverse(head)
 
    # Initialize pointer to maximum value node
    max = head
 
    # Traverse the reversed list
    temp = head.next
    while (temp != None):
     
        # Connect max through arbit pointer
        temp.arbit = max
 
        # Update max if required
        if (max.data < temp.data):
            max = temp
 
        # Move ahead in reversed list
        temp = temp.next
     
    # Reverse modified linked list and return
    # head.
    return reverse(head)
 
# Utility function to print result linked list
def printNextArbitPointers(node):
 
    print("Node\tNext Pointer\tArbit Pointer\n")
    while (node != None):
     
        print( node.data , "\t\t",end = "")
 
        if (node.next != None):
            print( node.next.data , "\t\t",end = "")
        else :
            print( "None" , "\t\t",end = "")
 
        if (node.arbit != None):
            print( node.arbit.data,end = "")
        else :
            print( "None",end = "")
         
        print("\n")
        node = node.next
     
# Function to create a new node with given data
def newNode(data):
 
    new_node = Node(0)
    new_node.data = data
    new_node.next = None
    return new_node
 
# Driver code
 
head = newNode(5)
head.next = newNode(10)
head.next.next = newNode(2)
head.next.next.next = newNode(3)
 
head = populateArbit(head)
 
print("Resultant Linked List is: \n")
printNextArbitPointers(head)
 
# This code is contributed by Arnab Kundu


C#




// C# program to point arbit pointers 
// to highest value on its right
using System;
 
class GfG
{
 
    /* Link list node */
    class Node
    {
        public int data;
        public Node next, arbit;
    }
 
    /* Function to reverse the linked list */
    static Node reverse(Node head)
    {
        Node prev = null, current = head, next = null;
        while (current != null)
        {
            next = current.next;
            current.next = prev;
            prev = current;
            current = next;
        }
        return prev;
    }
 
    // This function populates arbit pointer in every
    // node to the greatest value to its right.
    static Node populateArbit(Node head)
    {
        // Reverse given linked list
        head = reverse(head);
 
        // Initialize pointer to maximum value node
        Node max = head;
 
        // Traverse the reversed list
        Node temp = head.next;
        while (temp != null)
        {
            // Connect max through arbit pointer
            temp.arbit = max;
 
            // Update max if required
            if (max.data < temp.data)
                max = temp;
 
            // Move ahead in reversed list
            temp = temp.next;
        }
 
        // Reverse modified linked list 
        // and return head.
        return reverse(head);
    }
 
    // Utility function to print result linked list
    static void printNextArbitPointers(Node node)
    {
        Console.WriteLine("Node\tNext Pointer\tArbit Pointer");
        while (node != null)
        {
            Console.Write(node.data + "\t\t");
 
            if (node.next != null)
                Console.Write(node.next.data + "\t\t");
            else
                Console.Write("NULL" +"\t\t");
 
            if (node.arbit != null)
                Console.Write(node.arbit.data);
            else
                Console.Write("NULL");
 
            Console.WriteLine();
            node = node.next;
        }
    }
 
    /* Function to create a new node with given data */
    static Node newNode(int data)
    {
        Node new_node = new Node();
        new_node.data = data;
        new_node.next = null;
        return new_node;
    }
 
    /* Driver code*/
    public static void Main(String[] args)
    {
        Node head = newNode(5);
        head.next = newNode(10);
        head.next.next = newNode(2);
        head.next.next.next = newNode(3);
 
        head = populateArbit(head);
 
        Console.WriteLine("Resultant Linked List is: ");
        printNextArbitPointers(head);
    }
}
 
/* This code is contributed by 29AjayKumar */


Javascript




<script>
// javascript program to point arbit pointers to highest
// value on its right
 
 
    /* Link list node */
     class Node {
            constructor(val) {
                this.data = val;
                this.arbit = null;
                this.next = null;
            }
        }
     
 
    /* Function to reverse the linked list */
    function reverse(head) {
        var prev = null, current = head, next = null;
        while (current != null) {
            next = current.next;
            current.next = prev;
            prev = current;
            current = next;
        }
        return prev;
    }
 
    // This function populates arbit pointer in every
    // node to the greatest value to its right.
    function populateArbit(head) {
        // Reverse given linked list
        head = reverse(head);
 
        // Initialize pointer to maximum value node
        var max = head;
 
        // Traverse the reversed list
        var temp = head.next;
        while (temp != null) {
            // Connect max through arbit pointer
            temp.arbit = max;
 
            // Update max if required
            if (max.data < temp.data)
                max = temp;
 
            // Move ahead in reversed list
            temp = temp.next;
        }
 
        // Reverse modified linked list and return
        // head.
        return reverse(head);
    }
 
    // Utility function to print result linked list
    function printNextArbitPointers(node) {
        document.write("Node     Next Pointer    Arbit Pointer<br/>");
        while (node != null) {
            document.write(node.data + "          ");
 
            if (node.next != null)
                document.write(node.next.data + "                    ");
            else
                document.write("NULL" + "          ");
 
            if (node.arbit != null)
                document.write(node.arbit.data);
            else
                document.write("NULL");
 
            document.write("<br/>");
            node = node.next;
        }
    }
 
    /* Function to create a new node with given data */
    function newNode(data) {
        var new_node = new Node();
        new_node.data = data;
        new_node.next = null;
        return new_node;
    }
 
    /* Driver code */
     
        var head = newNode(5);
        head.next = newNode(10);
        head.next.next = newNode(2);
        head.next.next.next = newNode(3);
 
        head = populateArbit(head);
 
        document.write("Resultant Linked List is: <br/>");
        printNextArbitPointers(head);
 
 
// This code is contributed by umadevi9616
</script>


Output

Resultant Linked List is: 
Node    Next Pointer    Arbit Pointer
5        10        10
10        2        3
2        3        3
3        NULL        NULL

The time complexity of the reverse function is O(n) as it iterates over each node in the linked list once. 

The space complexity of the program is O(1).

Recursive Solution: We can recursively reach the last node and traverse the linked list from the end. The recursive solution doesn’t require reversing of the linked list. We can also use a stack in place of recursion to temporarily hold nodes. Thanks to Santosh Kumar Mishra for providing this solution. 

C++




// C++ program to point arbit pointers to highest
// value on its right
#include<bits/stdc++.h>
using namespace std;
 
/* Link list node */
struct Node
{
    int data;
    Node* next, *arbit;
};
 
// This function populates arbit pointer in every
// node to the greatest value to its right.
void populateArbit(Node *head)
{
    // using static maxNode to keep track of maximum
    // orbit node address on right side
    static Node *maxNode;
 
    // if head is null simply return the list
    if (head == NULL)
        return;
 
    /* if head->next is null it means we reached at
       the last node just update the max and maxNode */
    if (head->next == NULL)
    {
        maxNode = head;
        return;
    }
 
    /* Calling the populateArbit to the next node */
    populateArbit(head->next);
 
    /* updating the arbit node of the current
     node with the maximum value on the right side */
    head->arbit = maxNode;
 
    /* if current Node value id greater then
     the previous right node then  update it */
    if (head->data > maxNode->data)
        maxNode = head;
 
   return;
}
 
// Utility function to print result linked list
void printNextArbitPointers(Node *node)
{
    printf("Node\tNext Pointer\tArbit Pointer\n");
    while (node!=NULL)
    {
        cout << node->data << "\t\t";
 
        if(node->next)
            cout << node->next->data << "\t\t";
        else cout << "NULL" << "\t\t";
 
        if(node->arbit)
            cout << node->arbit->data;
        else cout << "NULL";
 
        cout << endl;
        node = node->next;
    }
}
 
/* Function to create a new node with given data */
Node *newNode(int data)
{
    Node *new_node = new Node;
    new_node->data = data;
    new_node->next = NULL;
    return new_node;
}
 
/* Driver program to test above functions*/
int main()
{
    Node *head = newNode(5);
    head->next = newNode(10);
    head->next->next = newNode(2);
    head->next->next->next = newNode(3);
 
    populateArbit(head);
 
    printf("Resultant Linked List is: \n");
    printNextArbitPointers(head);
 
    return 0;
}


Java




// Java program to point arbit pointers to highest
// value on its right
class GfG
{
 
    /* Link list node */
    static class Node
    {
        int data;
        Node next, arbit;
    }
 
    static Node maxNode;
 
    // This function populates arbit pointer in every
    // node to the greatest value to its right.
    static void populateArbit(Node head)
    {
 
        // if head is null simply return the list
        if (head == null)
            return;
 
        /* if head->next is null it means we reached at
        the last node just update the max and maxNode */
        if (head.next == null)
        {
            maxNode = head;
            return;
        }
 
        /* Calling the populateArbit to the next node */
        populateArbit(head.next);
 
        /* updating the arbit node of the current
        node with the maximum value on the right side */
        head.arbit = maxNode;
 
        /* if current Node value id greater then
        the previous right node then update it */
        if (head.data > maxNode.data)
            maxNode = head;
 
        return;
    }
 
    // Utility function to print result linked list
    static void printNextArbitPointers(Node node)
    {
        System.out.println("Node\tNext Pointer\tArbit Pointer");
        while (node != null)
        {
            System.out.print(node.data + "\t\t\t");
 
            if (node.next != null)
                System.out.print(node.next.data + "\t\t\t\t");
            else
                System.out.print("NULL" +"\t\t\t");
 
            if (node.arbit != null)
                System.out.print(node.arbit.data);
            else
                System.out.print("NULL");
 
            System.out.println();
            node = node.next;
        }
    }
 
    /* Function to create a new node with given data */
    static Node newNode(int data)
    {
        Node new_node = new Node();
        new_node.data = data;
        new_node.next = null;
        return new_node;
    }
 
    /* Driver code*/
    public static void main(String[] args)
    {
        Node head = newNode(5);
        head.next = newNode(10);
        head.next.next = newNode(2);
        head.next.next.next = newNode(3);
 
        populateArbit(head);
 
        System.out.println("Resultant Linked List is: ");
        printNextArbitPointers(head);
 
    }
}
 
// This code is contributed by shubham96301   


Python3




# Python3 program to point arbit pointers to highest
# value on its right
 
''' Link list node '''
# Node class
class newNode:
 
    # Constructor to initialize the node object
    def __init__(self, data):
        self.data = data
        self.next = None
        self.arbit = None
 
# This function populates arbit pointer in every
# node to the greatest value to its right.
maxNode = newNode(None)
def populateArbit(head):
     
    # using static maxNode to keep track of maximum
    # orbit node address on right side
    global maxNode
     
    # if head is null simply return the list
    if (head == None):
        return
         
    ''' if head.next is null it means we reached at
    the last node just update the max and maxNode '''
    if (head.next == None):
        maxNode = head
        return
         
    ''' Calling the populateArbit to the next node '''
    populateArbit(head.next)
     
    ''' updating the arbit node of the current
    node with the maximum value on the right side '''
    head.arbit = maxNode
     
    ''' if current Node value id greater then
    the previous right node then update it '''
    if (head.data > maxNode.data and maxNode.data != None ):
        maxNode = head
    return
 
# Utility function to print result linked list
def printNextArbitPointers(node):
    print("Node\tNext Pointer\tArbit Pointer")
    while (node != None):
        print(node.data,"\t\t", end = "")
        if(node.next):
            print(node.next.data,"\t\t", end = "")
        else:
            print("NULL","\t\t", end = "")
        if(node.arbit):
            print(node.arbit.data, end = "")
        else:
            print("NULL", end = "")
        print()
        node = node.next
         
''' Driver code'''
head = newNode(5)
head.next = newNode(10)
head.next.next = newNode(2)
head.next.next.next = newNode(3)
 
populateArbit(head)
 
print("Resultant Linked List is:")
printNextArbitPointers(head)
 
# This code is contributed by SHUBHAMSINGH10


C#




// C# program to point arbit pointers to highest
// value on its right
using System;
     
class GfG
{
 
    /* Link list node */
    public class Node
    {
        public int data;
        public Node next, arbit;
    }
 
    static Node maxNode;
 
    // This function populates arbit pointer in every
    // node to the greatest value to its right.
    static void populateArbit(Node head)
    {
 
        // if head is null simply return the list
        if (head == null)
            return;
 
        /* if head->next is null it means we reached at
        the last node just update the max and maxNode */
        if (head.next == null)
        {
            maxNode = head;
            return;
        }
 
        /* Calling the populateArbit to the next node */
        populateArbit(head.next);
 
        /* updating the arbit node of the current
        node with the maximum value on the right side */
        head.arbit = maxNode;
 
        /* if current Node value id greater then
        the previous right node then update it */
        if (head.data > maxNode.data)
            maxNode = head;
 
        return;
    }
 
    // Utility function to print result linked list
    static void printNextArbitPointers(Node node)
    {
        Console.WriteLine("Node\tNext Pointer\tArbit Pointer");
        while (node != null)
        {
            Console.Write(node.data + "\t\t\t");
 
            if (node.next != null)
                Console.Write(node.next.data + "\t\t\t\t");
            else
                Console.Write("NULL" +"\t\t\t");
 
            if (node.arbit != null)
                Console.Write(node.arbit.data);
            else
                Console.Write("NULL");
 
            Console.WriteLine();
            node = node.next;
        }
    }
 
    /* Function to create a new node with given data */
    static Node newNode(int data)
    {
        Node new_node = new Node();
        new_node.data = data;
        new_node.next = null;
        return new_node;
    }
 
    /* Driver code*/
    public static void Main(String[] args)
    {
        Node head = newNode(5);
        head.next = newNode(10);
        head.next.next = newNode(2);
        head.next.next.next = newNode(3);
 
        populateArbit(head);
 
        Console.WriteLine("Resultant Linked List is: ");
        printNextArbitPointers(head);
 
    }
}
 
/* This code contributed by PrinciRaj1992 */


Javascript




<script>
 
// Javascript program to point
// arbit pointers to highest
// value on its right
 
 
    /* Link list node */
 
     class Node {
        constructor() {
            this.data = 0;
            this.arbit = null;
            this.next = null;
        }
    }
 
    var maxNode;
 
    // This function populates arbit pointer in every
    // node to the greatest value to its right.
    function populateArbit(head) {
 
        // if head is null simply return the list
        if (head == null)
            return;
 
        /*
         if head->next is null it means we
         reached at the last node just update the
         max and maxNode
         */
        if (head.next == null) {
            maxNode = head;
            return;
        }
 
        /* Calling the populateArbit to the next node */
        populateArbit(head.next);
 
        /*
         updating the arbit node of the current
         node with the maximum value on the
         right side
         */
        head.arbit = maxNode;
 
        /*
         if current Node value id greater then
         the previous right node then update it
         */
        if (head.data > maxNode.data)
            maxNode = head;
 
        return;
    }
 
    // Utility function to print result linked list
    function printNextArbitPointers(node) {
        document.write(
        "Node Next Pointer Arbit Pointer<br/>"
        );
        while (node != null) {
            document.write(node.data +
            "     ");
 
            if (node.next != null)
                document.write(node.next.data +
                "     ");
            else
                document.write("NULL" +
                "   ");
 
            if (node.arbit != null)
                document.write(node.arbit.data);
            else
                document.write("NULL");
 
            document.write("<br/>");
            node = node.next;
        }
    }
 
    /* Function to create a new node with given data */
    function newNode(data) {
var new_node = new Node();
        new_node.data = data;
        new_node.next = null;
        return new_node;
    }
 
    /* Driver code */
     
        var head = newNode(5);
        head.next = newNode(10);
        head.next.next = newNode(2);
        head.next.next.next = newNode(3);
 
        populateArbit(head);
 
        document.write("Resultant Linked List is: <br/>");
        printNextArbitPointers(head);
 
 
// This code contributed by gauravrajput1
 
</script>


Output

Resultant Linked List is: 
Node    Next Pointer    Arbit Pointer
5        10        10
10        2        3
2        3        3
3        NULL        NULL

The time complexity of this program is O(n), where n is the length of the linked list.

The space complexity of this program is also O(n), where n is the length of the linked list. 



Last Updated : 06 Apr, 2023
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