XOR Linked List: Remove last node of the Linked List
Given an XOR linked list, the task is to delete the node at the end of the XOR Linked List.
Examples:
Input: 4<–>7<–>9<–>7
Output: 4<–>7<–>9
Explanation: Deleting a node from the end modifies the given XOR Linked List to 4<–>7<–>9Input: 10
Output: List is empty
Explanation: After deleting the only node present in the XOR Linked List, the list becomes empty.
Approach: The idea to solve this problem is to traverse the XOR linked list until the last node is reached and update the address of its previous node. Follow the steps below to solve the problem:
- If the XOR linked list is empty, then print “List is empty“.
- Traverse the XOR Linked List until the last node of the Linked List is reached.
- Update the address of its previous node.
- Delete the last node from memory.
- If the list becomes empty after deleting the last node, then print “List is empty”. Otherwise, print the remaining nodes of the linked list.
Below is the implementation of the above approach:
C++
// C++ program for the above approach #include <bits/stdc++.h> using namespace std; // Structure of a node in XOR linked list struct Node { // Stores data value of a node int data; // Stores XOR of previous pointer and next pointer struct Node* nxp; }; // Function to find the XOR of two nodes struct Node* XOR( struct Node* a, struct Node* b) { return ( struct Node*)(( uintptr_t )(a) ^ ( uintptr_t )(b)); } // Function to insert a node with given value at given position struct Node* insert( struct Node** head, int value) { // If XOR linked list is empty if (*head == NULL) { // Initialize a new Node struct Node* node = new Node; // Stores data value in the node node->data = value; // Stores XOR of previous and next pointer node->nxp = XOR(NULL, NULL); // Update pointer of head node *head = node; } // If the XOR linked list is not empty else { // Stores the address of current node struct Node* curr = *head; // Stores the address of previous node struct Node* prev = NULL; // Initialize a new Node struct Node* node = new Node; // Update curr node address curr->nxp = XOR(node, XOR(NULL, curr->nxp)); // Update new node address node->nxp = XOR(NULL, curr); // Update head *head = node; // Update data value of current node node->data = value; } return *head; } // Function to print elements of the XOR Linked List void printList( struct Node** head) { // Stores XOR pointer in current node struct Node* curr = *head; // Stores XOR pointer of in previous Node struct Node* prev = NULL; // Stores XOR pointer of in next node struct Node* next; // Traverse XOR linked list while (curr != NULL) { // Print current node cout << curr->data << " " ; // Forward traversal next = XOR(prev, curr->nxp); // Update prev prev = curr; // Update curr curr = next; } } // Function to delete the last node present in the XOR Linked List struct Node* delEnd( struct Node** head) { // Base condition if (*head == NULL) cout << "List is empty" ; else { // Stores XOR pointer in current node struct Node* curr = *head; // Stores XOR pointer of in previous Node struct Node* prev = NULL; // Stores XOR pointer of in next node struct Node* next; // Traverse XOR linked list while (XOR(curr->nxp, prev) != NULL) { // Forward traversal next = XOR(prev, curr->nxp); // Update prev prev = curr; // Update curr curr = next; } // If the Linked List contains more than 1 node if (prev != NULL) { prev->nxp = XOR(XOR(prev->nxp, curr), NULL); } // Otherwise else { *head = NULL; } // Delete the last node from memory delete (curr); } // Returns head of new linked list return *head; } // Driver Code int main() { /* Create the XOR Linked List head-->40<-->30<-->20<-->10 */ struct Node* head = NULL; insert(&head, 10); insert(&head, 20); insert(&head, 30); insert(&head, 40); delEnd(&head); // If the list had a single node if (head == NULL) cout << "List is empty" ; else // Print the list after deletion printList(&head); return (0); } // This code is contributed by ajaymakvana |
C
// C program for the above approach #include <inttypes.h> #include <stdio.h> #include <stdlib.h> // Structure of a node // in XOR linked list struct Node { // Stores data value // of a node int data; // Stores XOR of previous // pointer and next pointer struct Node* nxp; }; // Function to find the XOR of two nodes struct Node* XOR( struct Node* a, struct Node* b) { return ( struct Node*)(( uintptr_t )(a) ^ ( uintptr_t )(b)); } // Function to insert a node with // given value at given position struct Node* insert( struct Node** head, int value) { // If XOR linked list is empty if (*head == NULL) { // Initialize a new Node struct Node* node = ( struct Node*) malloc ( sizeof ( struct Node)); // Stores data value in // the node node->data = value; // Stores XOR of previous // and next pointer node->nxp = XOR(NULL, NULL); // Update pointer of head node *head = node; } // If the XOR linked list // is not empty else { // Stores the address // of current node struct Node* curr = *head; // Stores the address // of previous node struct Node* prev = NULL; // Initialize a new Node struct Node* node = ( struct Node*) malloc ( sizeof ( struct Node)); // Update curr node address curr->nxp = XOR(node, XOR(NULL, curr->nxp)); // Update new node address node->nxp = XOR(NULL, curr); // Update head *head = node; // Update data value of // current node node->data = value; } return *head; } // Function to print elements of // the XOR Linked List void printList( struct Node** head) { // Stores XOR pointer // in current node struct Node* curr = *head; // Stores XOR pointer of // in previous Node struct Node* prev = NULL; // Stores XOR pointer of // in next node struct Node* next; // Traverse XOR linked list while (curr != NULL) { // Print current node printf ( "%d " , curr->data); // Forward traversal next = XOR(prev, curr->nxp); // Update prev prev = curr; // Update curr curr = next; } } // Function to delete the last node // present in the XOR Linked List struct Node* delEnd( struct Node** head) { // Base condition if (*head == NULL) printf ( "List is empty" ); else { // Stores XOR pointer // in current node struct Node* curr = *head; // Stores XOR pointer of // in previous Node struct Node* prev = NULL; // Stores XOR pointer of // in next node struct Node* next; // Traverse XOR linked list while (XOR(curr->nxp, prev) != NULL) { // Forward traversal next = XOR(prev, curr->nxp); // Update prev prev = curr; // Update curr curr = next; } // If the Linked List contains more than 1 node if (prev != NULL) prev->nxp = XOR(XOR(prev->nxp, curr), NULL); // Otherwise else *head = NULL; // Delete the last node from memory free (curr); } // Returns head of new linked list return *head; } // Driver Code int main() { /* Create the XOR Linked List head-->40<-->30<-->20<-->10 */ struct Node* head = NULL; insert(&head, 10); insert(&head, 20); insert(&head, 30); insert(&head, 40); delEnd(&head); // If the list had a single node if (head == NULL) printf ( "List is empty" ); else // Print the list after deletion printList(&head); return (0); } |
Output:
40 30 20
Time Complexity: O(N)
Auxiliary Space: O(1)
Please Login to comment...