Given a Doubly linked list and Circular singly linked list containing N nodes, the task is to remove all the nodes from each list which contains elements whose parity is even.
Example:
Input: CLL = 9 -> 11 -> 34 -> 6 -> 13 -> 21
Output: 11 -> 13 -> 21
Explanation:
The circular singly linked list contains :
11 -> 1011, parity = 3
9 -> 1001, parity = 2
34 -> 100010, parity = 2
6 -> 110, parity = 2
13 -> 1101, parity = 3
21 -> 10101, parity = 3
Here, parity for nodes containing 9, 34, and 6 are even.
Hence, these nodes have been deleted.Input: DLL = 18 <=> 15 <=> 8 <=> 9 <=> 14
Output: 8 <=> 14
Explanation:
The linked list contains :
18 -> 10010, parity = 2
15 -> 1111, parity = 4
8 -> 1000, parity = 1
9 -> 1001, parity = 2
14 -> 1110, parity = 3
Here, parity for nodes containing 18, 15 and 9 are even.
Hence, these nodes have been deleted.
Approach:
A simple approach is to traverse the nodes of the list one by one and for each node first, find the parity for the value present in the node by iterating through each bit and then finally remove the nodes whose parity is even.
Doubly Linked List
Below is the implementation of the above approach:
C++
// C++ implementation to remove all // the Even Parity 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 that returns true if count // of set bits in x is even bool isEvenParity( int x) { // parity will store the // count of set bits int parity = 0; while (x != 0) { if (x & 1) parity++; x = x >> 1; } if (parity % 2 == 0) return true ; else return false ; } // 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 Parity Nodes from a // doubly linked list void deleteEvenParityNodes( 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 parity // is even if (isEvenParity(ptr->data)) deleteNode(head_ref, ptr); ptr = next; } } // Function to print nodes in a // given doubly linked list void printList(Node* head) { if (head == NULL) { cout << "Empty list\n" ; return ; } 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); // Uncomment to view the list // cout << "Original List: "; // printList(head); deleteEvenParityNodes(&head); // Modified List printList(head); } |
Python3
# Python3 implementation to remove all # the Even Parity 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 None 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 that returns true if count # of set bits in x is even def isEvenParity(x): # parity will store the # count of set bits parity = 0 while (x ! = 0 ): if (x & 1 ): parity + = 1 x = x >> 1 if (parity % 2 = = 0 ): return True else : return False # Function to delete a node # in a Doubly Linked List. # head_ref -. pointer to head node pointer. # delt -. pointer to node to be deleted def deleteNode(head_ref, delt): # Base case if (head_ref = = None or delt = = None ): return # If the node to be # deleted is head node if (head_ref = = delt): head_ref = delt. next # Change next only if node to be # deleted is not the last node if (delt. next ! = None ): delt. next .prev = delt.prev # Change prev only if node to be # deleted is not the first node if (delt.prev ! = None ): delt.prev. next = delt. next # Finally, free the memory # occupied by delt del (delt) return head_ref # Function to to remove all # the Even Parity Nodes from a # doubly linked list def deleteEvenParityNodes(head_ref): ptr = head_ref next = None # Iterating through # the linked list while (ptr ! = None ): next = ptr. next # If node's data's parity # is even if (isEvenParity(ptr.data)): head_ref = deleteNode(head_ref, ptr) ptr = next return head_ref # Function to print nodes in a # given doubly linked list def printList(head): if (head = = None ): print ( "Empty list\n" ) return 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 ) # Uncomment to view the list # cout << "Original List: "; # printList(head); head = deleteEvenParityNodes(head) # Modified List printList(head) # This code is contributed by rutvik_56 |
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Circular Singly Linked List
Below is the implementation of the above approach:
C++
// C++ program to remove all // the Even Parity Nodes from a // circular singly linked list #include <bits/stdc++.h> using namespace std; // Structure for a node struct Node { int data; struct Node* next; }; // Function to insert a node at the beginning // of a Circular linked list void push( struct Node** head_ref, int data) { // Create a new node // and make head as next // of it. struct Node* ptr1 = ( struct Node*) malloc ( sizeof ( struct Node)); struct Node* temp = *head_ref; ptr1->data = data; ptr1->next = *head_ref; // If linked list is not NULL then // set the next of last node if (*head_ref != NULL) { // Find the node before head // and update next of it. while (temp->next != *head_ref) temp = temp->next; temp->next = ptr1; } else // Point for the first node ptr1->next = ptr1; *head_ref = ptr1; } // Function to delete the node from a // Circular Linked list void deleteNode( Node*& head_ref, Node* del) { // If node to be deleted is head node if (head_ref == del) head_ref = del->next; struct Node* temp = head_ref; // Traverse list till not found // delete node while (temp->next != del) { temp = temp->next; } // Copy the address of the node temp->next = del->next; // Finally, free the memory // occupied by del free (del); return ; } // Function that returns true if count // of set bits in x is even bool isEvenParity( int x) { // parity will store the // count of set bits int parity = 0; while (x != 0) { if (x & 1) parity++; x = x >> 1; } if (parity % 2 == 0) return true ; else return false ; } // Function to delete all // the Even Parity Nodes // from the singly circular linked list void deleteEvenParityNodes(Node*& head) { if (head == NULL) return ; if (head == head->next) { if (isEvenParity(head->data)) head = NULL; return ; } struct Node* ptr = head; struct Node* next; // Traverse the list till the end do { next = ptr->next; // If the node's data has even parity, // delete node 'ptr' if (isEvenParity(ptr->data)) deleteNode(head, ptr); // Point to the next node ptr = next; } while (ptr != head); if (head == head->next) { if (isEvenParity(head->data)) head = NULL; return ; } } // Function to print nodes in a // given Circular linked list void printList( struct Node* head) { if (head == NULL) { cout << "Empty List\n" ; return ; } struct Node* temp = head; if (head != NULL) { do { printf ( "%d " , temp->data); temp = temp->next; } while (temp != head); } } // Driver code int main() { // Initialize lists as empty struct Node* head = NULL; // Created linked list will be // 11->9->34->6->13->21 push(&head, 21); push(&head, 13); push(&head, 6); push(&head, 34); push(&head, 9); push(&head, 11); deleteEvenParityNodes(head); printList(head); return 0; } |
Java
// Java program to remove all // the Even Parity Nodes from a // circular singly linked list class GFG{ // Structure for a node static class Node { int data; Node next; }; // Function to insert a node at // the beginning of a Circular // linked list static Node push(Node head_ref, int data) { // Create a new node // and make head as next // of it. Node ptr1 = new Node(); Node temp = head_ref; ptr1.data = data; ptr1.next = head_ref; // If linked list is not null then // set the next of last node if (head_ref != null ) { // Find the node before head // and update next of it. while (temp.next != head_ref) temp = temp.next; temp.next = ptr1; } else // Point for the first node ptr1.next = ptr1; head_ref = ptr1; return head_ref; } // Function to delete the node // from a Circular Linked list static void deleteNode(Node head_ref, Node del) { // If node to be deleted is // head node if (head_ref == del) head_ref = del.next; Node temp = head_ref; // Traverse list till not found // delete node while (temp.next != del) { temp = temp.next; } // Copy the address of the node temp.next = del.next; // Finally, free the memory // occupied by del System.gc(); return ; } // Function that returns true if count // of set bits in x is even static boolean isEvenParity( int x) { // Parity will store the // count of set bits int parity = 0 ; while (x != 0 ) { if ((x & 1 ) != 0 ) parity++; x = x >> 1 ; } if (parity % 2 == 0 ) return true ; else return false ; } // Function to delete all the // Even Parity Nodes from the // singly circular linked list static void deleteEvenParityNodes(Node head) { if (head == null ) return ; if (head == head.next) { if (isEvenParity(head.data)) head = null ; return ; } Node ptr = head; Node next; // Traverse the list till the end do { next = ptr.next; // If the node's data has // even parity, delete node 'ptr' if (isEvenParity(ptr.data)) deleteNode(head, ptr); // Point to the next node ptr = next; } while (ptr != head); if (head == head.next) { if (isEvenParity(head.data)) head = null ; return ; } } // Function to print nodes in a // given Circular linked list static void printList(Node head) { if (head == null ) { System.out.print( "Empty List\n" ); return ; } Node temp = head; if (head != null ) { do { System.out.printf( "%d " , temp.data); temp = temp.next; } while (temp != head); } } // Driver code public static void main(String[] args) { // Initialize lists as empty Node head = null ; // Created linked list will be // 11.9.34.6.13.21 head = push(head, 21 ); head = push(head, 13 ); head = push(head, 6 ); head = push(head, 34 ); head = push(head, 9 ); head = push(head, 11 ); deleteEvenParityNodes(head); printList(head); } } // This code is contributed by Amit Katiyar |
Python3
# Python3 program to remove all # the Even Parity Nodes from a # circular singly linked list # Structure for a node class Node: def __init__( self ): self .data = 0 self . next = None # Function to insert a node at the beginning # of a Circular linked list def push(head_ref, data): # Create a new node # and make head as next # of it. ptr1 = Node() temp = head_ref; ptr1.data = data; ptr1. next = head_ref; # If linked list is not None then # set the next of last node if (head_ref ! = None ): # Find the node before head # and update next of it. while (temp. next ! = head_ref): temp = temp. next ; temp. next = ptr1; else : # Pofor the first node ptr1. next = ptr1; head_ref = ptr1; return head_ref # Function to deltete the node from a # Circular Linked list def delteteNode( head_ref, delt): # If node to be delteted is head node if (head_ref = = delt): head_ref = delt. next ; temp = head_ref; # Traverse list till not found # deltete node while (temp. next ! = delt): temp = temp. next ; # Copy the address of the node temp. next = delt. next ; # Finally, free the memory # occupied by delt del (delt); return head_ref; # Function that returns true if count # of set bits in x is even def isEvenParity(x): # parity will store the # count of set bits parity = 0 ; while (x ! = 0 ): if (x & 1 ) ! = 0 : parity + = 1 x = x >> 1 ; if (parity % 2 = = 0 ): return True ; else : return False ; # Function to deltete all # the Even Parity Nodes # from the singly circular linked list def delteteEvenParityNodes(head): if (head = = None ): return head; if (head = = head. next ): if (isEvenParity(head.data)): head = None ; return head; ptr = head; next = None # Traverse the list till the end while True : next = ptr. next ; # If the node's data has even parity, # deltete node 'ptr' if (isEvenParity(ptr.data)): head = delteteNode(head, ptr); # Poto the next node ptr = next ; if (ptr = = head): break if (head = = head. next ): if (isEvenParity(head.data)): head = None ; return head; return head; # Function to prnodes in a # given Circular linked list def printList(head): if (head = = None ): print ( "Empty List" ) return ; temp = head; if (head ! = None ): while True : print (temp.data, end = ' ' ) temp = temp. next if temp = = head: break # Driver code if __name__ = = '__main__' : # Initialize lists as empty head = None ; # Created linked list will be # 11.9.34.6.13.21 head = push(head, 21 ); head = push(head, 13 ); head = push(head, 6 ); head = push(head, 34 ); head = push(head, 9 ); head = push(head, 11 ); head = delteteEvenParityNodes(head); printList(head); # This code is contributed by pratham_76 |
C#
// C# program to remove all // the Even Parity Nodes from a // circular singly linked list using System; class GFG{ // Structure for a node public class Node { public int data; public Node next; }; // Function to insert a node at // the beginning of a Circular // linked list static Node push(Node head_ref, int data) { // Create a new node // and make head as next // of it. Node ptr1 = new Node(); Node temp = head_ref; ptr1.data = data; ptr1.next = head_ref; // If linked list is not // null then set the next // of last node if (head_ref != null ) { // Find the node before head // and update next of it. while (temp.next != head_ref) temp = temp.next; temp.next = ptr1; } else // Point for the first node ptr1.next = ptr1; head_ref = ptr1; return head_ref; } // Function to delete the node // from a Circular Linked list static void deleteNode(Node head_ref, Node del) { // If node to be deleted is // head node if (head_ref == del) head_ref = del.next; Node temp = head_ref; // Traverse list till not // found delete node while (temp.next != del) { temp = temp.next; } // Copy the address of // the node temp.next = del.next; return ; } // Function that returns true // if count of set bits in x // is even static bool isEvenParity( int x) { // Parity will store the // count of set bits int parity = 0; while (x != 0) { if ((x & 1) != 0) parity++; x = x >> 1; } if (parity % 2 == 0) return true ; else return false ; } // Function to delete all the // Even Parity Nodes from the // singly circular linked list static void deleteEvenParityNodes(Node head) { if (head == null ) return ; if (head == head.next) { if (isEvenParity(head.data)) head = null ; return ; } Node ptr = head; Node next; // Traverse the list // till the end do { next = ptr.next; // If the node's data has // even parity, delete node 'ptr' if (isEvenParity(ptr.data)) deleteNode(head, ptr); // Point to the next node ptr = next; } while (ptr != head); if (head == head.next) { if (isEvenParity(head.data)) head = null ; return ; } } // Function to print nodes in a // given Circular linked list static void printList(Node head) { if (head == null ) { Console.Write( "Empty List\n" ); return ; } Node temp = head; if (head != null ) { do { Console.Write(temp.data + " " ); temp = temp.next; } while (temp != head); } } // Driver code public static void Main(String[] args) { // Initialize lists as empty Node head = null ; // Created linked list will be // 11.9.34.6.13.21 head = push(head, 21); head = push(head, 13); head = push(head, 6); head = push(head, 34); head = push(head, 9); head = push(head, 11); deleteEvenParityNodes(head); printList(head); } } // This code is contributed by Rajput-Ji |
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Time Complexity: O(K*N), where N is the size of the linked list and K is the number of bits in the maximum number present in the linked list.
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