Delete all Non-Prime Nodes from a Singly Linked List
Given a singly linked list containing N nodes, the task is to delete all nodes from the list which are not prime.
Examples:
Input : List = 15 -> 16 -> 6 -> 7 -> 17
Output : Final List = 7 -> 17
Input : List = 15 -> 3 -> 4 -> 2 -> 9
Output : Final List = 3 ->2
Approach: The idea is to traverse the nodes of the singly linked list one by one and get the pointer of the nodes which are not prime. Delete those nodes by following the approach used in the post: Delete a node from Linked List.
Below is the implementation of above idea:
C++
// C++ implementation to delete all// non-prime nodes from the singly// linked list#include <bits/stdc++.h>using namespace std;// Node of the singly linked liststruct Node { int data; Node* next;};// function to insert a node at the beginning// of the singly Linked Listvoid push(Node** head_ref, int new_data){ Node* new_node = new Node; new_node->data = new_data; new_node->next = (*head_ref); (*head_ref) = new_node;}// Function to check if a number is primebool isPrime(int n){ // Corner cases if (n <= 1) return false; if (n <= 3) return true; // This is checked so that we can skip // middle five numbers in below loop if (n % 2 == 0 || n % 3 == 0) return false; for (int i = 5; i * i <= n; i = i + 6) if (n % i == 0 || n % (i + 2) == 0) return false; return true;}// function to delete all non-prime nodes// from the singly linked listvoid deleteNonPrimeNodes(Node** head_ref){ // Remove all composite nodes at the beginning Node* ptr = *head_ref; while (ptr != NULL && !isPrime(ptr->data)) { Node *temp = ptr; ptr = ptr->next; delete(temp); } *head_ref = ptr; if (ptr == NULL) return; // Remove remaining nodes Node *curr = ptr->next; while (curr != NULL) { if (!isPrime(curr->data)) { ptr->next = curr->next; delete(curr); curr = ptr->next; } else { ptr = curr; curr = curr->next; } } }// function to print nodes in a// given singly linked listvoid printList(Node* head){ while (head != NULL) { cout << head->data << " "; head = head->next; }}// Driver programint main(){ // start with the empty list Node* head = NULL; // create the linked list // 15 -> 16 -> 7 -> 6 -> 17 push(&head, 17); push(&head, 7); push(&head, 6); push(&head, 16); push(&head, 15); cout << "Original List: "; printList(head); deleteNonPrimeNodes(&head); cout << "\nModified List: "; printList(head);} |
Java
// Java implementation to delete all// non-prime nodes from the singly// linked listclass GFG{ // Node of the singly linked liststatic class Node{ int data; Node next;};// function to insert a node at the beginning// of the singly Linked Liststatic Node push(Node head_ref, int new_data){ Node new_node = new Node(); new_node.data = new_data; new_node.next = (head_ref); (head_ref) = new_node; return head_ref;}// Function to check if a number is primestatic boolean isPrime(int n){ // Corner cases if (n <= 1) return false; if (n <= 3) return true; // This is checked so that we can skip // middle five numbers in below loop if (n % 2 == 0 || n % 3 == 0) return false; for (int i = 5; i * i <= n; i = i + 6) if (n % i == 0 || n % (i + 2) == 0) return false; return true;}// function to delete all non-prime nodes// from the singly linked liststatic Node deleteNonPrimeNodes(Node head_ref){ // Remove all composite nodes at the beginning Node ptr = head_ref; while (ptr != null && !isPrime(ptr.data)) { Node temp = ptr; ptr = ptr.next; } head_ref = ptr; if (ptr == null) return null; // Remove remaining nodes Node curr = ptr.next; while (curr != null) { if (!isPrime(curr.data)) { ptr.next = curr.next; curr = ptr.next; } else { ptr = curr; curr = curr.next; } } return head_ref;}// function to print nodes in a// given singly linked liststatic void printList(Node head){ while (head != null) { System.out.print(head.data + " "); head = head.next; }}// Driver codepublic static void main(String args[]){ // start with the empty list Node head = null; // create the linked list // 15 . 16 . 7 . 6 . 17 head = push(head, 17); head = push(head, 7); head = push(head, 6); head = push(head, 16); head = push(head, 15); System.out.print("Original List: "); printList(head); head = deleteNonPrimeNodes(head); System.out.print("\nModified List: "); printList(head);}}// This code is contributed by Arnab Kundu |
Python3
# Python3 implementation to delete all# non-prime nodes from the singly# linked listimport math# Node of the singly linked listclass Node: def __init__(self, data): self.data = data self.next = None# function to insert a node at the beginning# of the singly Linked Listdef push(head_ref, new_data): new_node = Node(new_data) new_node.data = new_data new_node.next = head_ref head_ref = new_node return head_ref# Function to check if a number is primedef isPrime(n): # Corner cases if (n <= 1): return False if (n <= 3): return True # This is checked so that we can skip # middle five numbers in below loop if (n % 2 == 0 or n % 3 == 0): return False for i in range(5, n + 1, 6): if (i * i < n + 2 and (n % i == 0 or n % (i + 2) == 0)): return False return True# function to delete all non-prime nodes# from the singly linked listdef deleteNonPrimeNodes(head_ref): # Remove all composite nodes at the beginning ptr = head_ref while (ptr != None and isPrime(ptr.data)!= True): temp = ptr ptr = ptr.next # delete(temp) head_ref = ptr if (ptr == None): return None # Remove remaining nodes curr = ptr.next while (curr != None) : if (isPrime(curr.data) != True): ptr.next = curr.next #delete(curr) curr = ptr.next else: ptr = curr curr = curr.next return head_ref # function to print nodes in a# given singly linked listdef printList( head): while (head != None) : print(head.data, end = " ") head = head.next # Driver Codeif __name__=='__main__': # start with the empty list head = None # create the linked list # 15 -> 16 -> 7 -> 6 -> 17 head = push(head, 17) head = push(head, 7) head = push(head, 6) head = push(head, 16) head = push(head, 15) print("Original List: ") printList(head) head = deleteNonPrimeNodes(head) print("\nModified List: ") printList(head)# This code is contributed by AbhiThakur |
C#
// C# implementation to delete all// non-prime nodes from the singly// linked listusing System;class GFG{ // Node of the singly linked list public 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) { Node new_node = new Node(); new_node.data = new_data; new_node.next = (head_ref); (head_ref) = new_node; return head_ref; } // Function to check if a number is prime static bool isPrime(int n) { // Corner cases if (n <= 1) { return false; } if (n <= 3) { return true; } // This is checked so that we can skip // middle five numbers in below loop if (n % 2 == 0 || n % 3 == 0) { return false; } for (int i = 5; i * i <= n; i = i + 6) { if (n % i == 0 || n % (i + 2) == 0) { return false; } } return true; } // function to delete all non-prime nodes // from the singly linked list static Node deleteNonPrimeNodes(Node head_ref) { // Remove all composite nodes // at the beginning Node ptr = head_ref; while (ptr != null && !isPrime(ptr.data)) { Node temp = ptr; ptr = ptr.next; } head_ref = ptr; if (ptr == null) { return null; } // Remove remaining nodes Node curr = ptr.next; while (curr != null) { if (!isPrime(curr.data)) { ptr.next = curr.next; curr = ptr.next; } else { ptr = curr; curr = curr.next; } } return head_ref; } // function to print nodes in a // given singly 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 linked list // 15 . 16 . 7 . 6 . 17 head = push(head, 17); head = push(head, 7); head = push(head, 6); head = push(head, 16); head = push(head, 15); Console.Write("Original List: "); printList(head); head = deleteNonPrimeNodes(head); Console.Write("\nModified List: "); printList(head); }}// This code is contributed by 29AjayKumar |
Javascript
<script>// javascript implementation to delete all// non-prime nodes from the singly// linked list // Node of the singly linked listclass Node { constructor() { this.data = 0; this.next = null; }} // function to insert a node at the beginning // of the singly Linked List function push(head_ref , new_data) {var new_node = new Node(); new_node.data = new_data; new_node.next = (head_ref); (head_ref) = new_node; return head_ref; } // Function to check if a number is prime function isPrime(n) { // Corner cases if (n <= 1) return false; if (n <= 3) return true; // This is checked so that we can skip // middle five numbers in below loop if (n % 2 == 0 || n % 3 == 0) return false; for (i = 5; i * i <= n; i = i + 6) if (n % i == 0 || n % (i + 2) == 0) return false; return true; } // function to delete all non-prime nodes // from the singly linked list function deleteNonPrimeNodes(head_ref) { // Remove all composite nodes at the beginningvar ptr = head_ref; while (ptr != null && !isPrime(ptr.data)) { var temp = ptr; ptr = ptr.next; } head_ref = ptr; if (ptr == null) return null; // Remove remaining nodesvar curr = ptr.next; while (curr != null) { if (!isPrime(curr.data)) { ptr.next = curr.next; curr = ptr.next; } else { ptr = curr; curr = curr.next; } } return head_ref; } // function to prvar nodes in a // given singly linked list function printList(head) { while (head != null) { document.write(head.data + " "); head = head.next; } } // Driver code // start with the empty listvar head = null; // create the linked list // 15 . 16 . 7 . 6 . 17 head = push(head, 17); head = push(head, 7); head = push(head, 6); head = push(head, 16); head = push(head, 15); document.write("Original List: "); printList(head); head = deleteNonPrimeNodes(head); document.write("<br/>Modified List: "); printList(head);// This code contributed by aashish1995</script> |
Output:
Original List: 15 16 6 7 17 Modified List: 7 17
Attention reader! Don’t stop learning now. Get hold of all the important DSA concepts with the DSA Self Paced Course at a student-friendly price and become industry ready. To complete your preparation from learning a language to DS Algo and many more, please refer Complete Interview Preparation Course.
In case you wish to attend live classes with industry experts, please refer Geeks Classes Live
