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Delete all the nodes from the list which are divisible by any given number K

  • Last Updated : 25 Jun, 2021

Given a Linked List and a key K. The task is to write a program to delete all the nodes from the list that are divisible by K.
Examples: 
 

Input : 12->15->9->11->5->6->7
        K = 3
Output :  11 -> 5 -> 7

Input :13->4->16->9->22->45->5->16->6
        K = 4
Output : 13 -> 9 -> 22 -> 45 -> 5 -> 6

 

The approach to solving this problem is similar to deleting all nodes from the list which are lesser than the given key.
There are two possible cases: 
 

  1. Head node holds a value divisible by K: First check for all occurrences at head node which are divisible by K, delete them and change the head node appropriately.
  2. Some intermediate node holds value divisible by k: Start traversing from head and check if current node’s value is divisible by K. If yes then delete that node and move forward in the list.

Below is the implementation of the above approach: 
 

C++




// C++ program to delete all the nodes from the list
// that are divisible by  the specified value K
#include <bits/stdc++.h>
 
using namespace std;
 
// Tree Node
struct Node {
    int data;
    Node* next;
};
 
// Function to create a new node
Node* getNode(int data)
{
    Node* newNode = new Node;
    newNode->data = data;
    newNode->next = NULL;
    return newNode;
}
 
// Function to delete all the nodes from the list
// that divisible by the specified value K
void deleteDivisibleNodes(Node** head_ref, int K)
{
    Node *temp = *head_ref, *prev;
 
    // If head node itself holds the value divisible by K
    while (temp != NULL && temp->data % K == 0) {
        *head_ref = temp->next; // Changed head
        free(temp); // free old head
        temp = *head_ref; // Change temp
    }
 
    // Delete occurrences other than head
    while (temp != NULL) {
 
        // Search for the node to be deleted,
        // keep track of the previous node as we
        // need to change 'prev->next'
        while (temp != NULL && temp->data % K != 0) {
            prev = temp;
            temp = temp->next;
        }
 
        // If required value node was not present
        // in linked list
        if (temp == NULL)
            return;
 
        // Unlink the node from linked list
        prev->next = temp->next;
 
        delete temp; // Free memory
 
        // Update Temp for next iteration of
        // outer loop
        temp = prev->next;
    }
}
 
// function to a print a linked list
void printList(Node* head)
{
    while (head) {
        cout << head->data << " ";
        head = head->next;
    }
}
 
// Driver code
int main()
{
    // Create list: 12->15->9->11->5->6->7
    Node* head = getNode(12);
    head->next = getNode(15);
    head->next->next = getNode(9);
    head->next->next->next = getNode(11);
    head->next->next->next->next = getNode(5);
    head->next->next->next->next->next = getNode(6);
    head->next->next->next->next->next->next = getNode(7);
    int K = 3;
 
    cout << "Initial List: ";
    printList(head);
 
    deleteDivisibleNodes(&head, K);
 
    cout << "\nFinal List: ";
    printList(head);
 
    return 0;
}

Java




// Java program to delete all the nodes from the list
// that are divisible by the specified value K
import java.util.*;
 
class GFG
{
 
// Tree Node
static class Node
{
    int data;
    Node next;
};
 
// Function to create a new node
static Node getNode(int data)
{
    Node newNode = new Node();
    newNode.data = data;
    newNode.next = null;
    return newNode;
}
 
// Function to delete all the nodes from the list
// that divisible by the specified value K
static Node deleteDivisibleNodes(Node head_ref, int K)
{
    Node temp = head_ref, prev = null;
 
    // If head node itself holds the value divisible by K
    while (temp != null && temp.data % K == 0)
    {
        head_ref = temp.next; // Changed head
        //free(temp); // free old head
        temp = head_ref; // Change temp
    }
 
    // Delete occurrences other than head
    while (temp != null)
    {
 
        // Search for the node to be deleted,
        // keep track of the previous node as we
        // need to change 'prev.next'
        while (temp != null && temp.data % K != 0)
        {
            prev = temp;
            temp = temp.next;
        }
 
        // If required value node was not present
        // in linked list
        if (temp == null)
            return head_ref;
 
        // Unlink the node from linked list
        prev.next = temp.next;
 
        //delete temp; // Free memory
 
        // Update Temp for next iteration of
        // outer loop
        temp = prev.next;
    }
    return null;
}
 
// function to a print a 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)
{
    // Create list: 12->15->9->11->5->6->7
    Node head = getNode(12);
    head.next = getNode(15);
    head.next.next = getNode(9);
    head.next.next.next = getNode(11);
    head.next.next.next.next = getNode(5);
    head.next.next.next.next.next = getNode(6);
    head.next.next.next.next.next.next = getNode(7);
    int K = 3;
 
    System.out.print("Initial List: ");
    printList(head);
 
    head = deleteDivisibleNodes(head, K);
 
    System.out.print("\nFinal List: ");
    printList(head);
}
}
 
// This code is contributed by PrinciRaj1992

Python3




# Python3 program to delete all the
# nodes from the list that are
# divisible by the specified value K
 
# Node class
class Node:
     
    # Function to initialize the node object
    def __init__(self, data):
         
        self.data = data
        self.next = None
     
# Linked List Class
class LinkedList:
 
    # Function to initialize the
    # LinkedList class.
    def __init__(self):
 
        # Initialize head as None
        self.head = None
 
    # This Method insert a new node
    # at the End of the list
    def push(self, new_data):
 
        # Taking a pointer to iterate
        ptr = self.head
 
        # Making a new node with
        # given data as it's element
        new_node = Node(new_data)
 
        # assigning the first node to
        # head if list is empty or DNE
        if(ptr == None):
            self.head = new_node
 
        # If list exits then..
        else:
             
            # Iteraring to the last
            # node of the list
            while(ptr.next != None):
                ptr = ptr.next
 
            # Attatching new node at
            # the end of list
            ptr.next = new_node
 
    # Method to delete Nodes divisible
    # by given integer.
    def deleteDivisibleNodes(self, K):
 
        # Declaring a temporary object
        # containing address of head
        temp = self.head
 
        # Deleting the first node if it's
        # data is divisible by given integer
        # repeat till first node gets
        # indivisible.
        while(temp != None and
             (temp.data % K) == 0):
            self.head = temp.next
            del(temp)
            temp = self.head
 
        # Now iterating through each node
        # of the list.
        while(temp != None):
 
            # Checking if data in current node is
            # divisible by given element and move
            # to next node till it gets not divisible.
            while(temp != None and
                 (temp.data % K) != 0):
                prev = temp
                temp = temp.next
 
            # Returning if list ends
            if(temp == None):
                return
 
            # Else storing address of next node
            # in next of previous node
            prev.next = temp.next
 
            # And deleting the current Node
            del(temp)
 
            # Then move to next node and repeat
            # the loop till list ends.
            temp = prev.next
 
    # Method to print the linked list
    def printList(self):
         
        ptr = self.head
         
        while(ptr != None):
            x = ptr.data
            print(x, ' ', end = '')
            ptr = ptr.next
             
        print()
 
# Driver Code
if __name__=='__main__':
 
    # Start with empty list
    head = LinkedList()
 
    # Create the linked list Adding
    # a new node at End of the list
    head.push(12)
    head.push(15)
    head.push(9)
    head.push(11)
    head.push(5)
    head.push(6)
    head.push(7)
 
    print("Initila List: ", end = '')
    head.printList()
 
    K = 3
    head.deleteDivisibleNodes(K)
 
    print("Final List: ", end = '')
    head.printList()
 
# This code is contributed by Amit Mangal

C#




// C# program to delete all the nodes
// from the list that are divisible
// by the specified value K
using System;
 
class GFG
{
 
// Tree Node
public class Node
{
    public int data;
    public Node next;
};
 
// Function to create a new node
static Node getNode(int data)
{
    Node newNode = new Node();
    newNode.data = data;
    newNode.next = null;
    return newNode;
}
 
// Function to delete all the nodes
// from the list that divisible by
// the specified value K
static Node deleteDivisibleNodes(Node head_ref,
                                         int K)
{
    Node temp = head_ref, prev = null;
 
    // If head node itself holds
    // the value divisible by K
    while (temp != null &&
           temp.data % K == 0)
    {
        head_ref = temp.next; // Changed head
        //free(temp); // free old head
        temp = head_ref; // Change temp
    }
 
    // Delete occurrences other than head
    while (temp != null)
    {
 
        // Search for the node to be deleted,
        // keep track of the previous node as we
        // need to change 'prev.next'
        while (temp != null &&
               temp.data % K != 0)
        {
            prev = temp;
            temp = temp.next;
        }
 
        // If required value node
        // was not present in linked list
        if (temp == null)
            return head_ref;
 
        // Unlink the node from linked list
        prev.next = temp.next;
 
        //delete temp; // Free memory
 
        // Update Temp for next iteration of
        // outer loop
        temp = prev.next;
    }
    return null;
}
 
// function to a print a 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)
{
    // Create list: 12->15->9->11->5->6->7
    Node head = getNode(12);
    head.next = getNode(15);
    head.next.next = getNode(9);
    head.next.next.next = getNode(11);
    head.next.next.next.next = getNode(5);
    head.next.next.next.next.next = getNode(6);
    head.next.next.next.next.next.next = getNode(7);
    int K = 3;
 
    Console.Write("Initial List: ");
    printList(head);
 
    head = deleteDivisibleNodes(head, K);
 
    Console.Write("\nFinal List: ");
    printList(head);
}
}
 
// This code is contributed by PrinciRaj1992

Javascript




<script>
 
// JavaScript program to delete
// all the nodes from the list
// that are divisible by the specified value K
 
    // Tree Node
class Node {
    constructor(val) {
        this.data = val;
        this.next = null;
    }
}
 
    // Function to create a new node
    function getNode(data) {
        var newNode = new Node();
        newNode.data = data;
        newNode.next = null;
        return newNode;
    }
 
    // Function to delete all the nodes from the list
    // that divisible by the specified value K
    function deleteDivisibleNodes(head_ref , K) {
     var temp = head_ref, prev = null;
 
        // If head node itself holds
        // the value divisible by K
        while (temp != null && temp.data % K == 0) {
            head_ref = temp.next; // Changed head
            // free(temp); // free old head
            temp = head_ref; // Change temp
        }
 
        // Delete occurrences other than head
        while (temp != null) {
 
            // Search for the node to be deleted,
            // keep track of the previous node as we
            // need to change 'prev.next'
            while (temp != null && temp.data % K != 0) {
                prev = temp;
                temp = temp.next;
            }
 
            // If required value node was not present
            // in linked list
            if (temp == null)
                return head_ref;
 
            // Unlink the node from linked list
            prev.next = temp.next;
 
            // delete temp; // Free memory
 
            // Update Temp for next iteration of
            // outer loop
            temp = prev.next;
        }
        return null;
    }
 
    // function to a prvar a linked list
    function printList(head) {
        while (head != null) {
            document.write(head.data + " ");
            head = head.next;
        }
    }
 
    // Driver code
     
        // Create list: 12->15->9->11->5->6->7
        var head = getNode(12);
        head.next = getNode(15);
        head.next.next = getNode(9);
        head.next.next.next = getNode(11);
        head.next.next.next.next = getNode(5);
        head.next.next.next.next.next = getNode(6);
        head.next.next.next.next.next.next = getNode(7);
        var K = 3;
 
        document.write("Initial List: ");
        printList(head);
 
        head = deleteDivisibleNodes(head, K);
 
        document.write("<br/>Final List: ");
        printList(head);
 
// This code contributed by umadevi9616
 
</script>
Output: 
Initial List: 12 15 9 11 5 6 7 
Final List: 11 5 7

 

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