Remove last node of the linked list
Given a linked list, the task is to remove the last node of the linked list and update the head pointer of the linked list.
Examples:
Input: 1 -> 2 -> 3 -> 4 -> 5 -> NULL Output: 1 -> 2 -> 3 -> 4 -> NULL Explanation: The last node of the linked list is 5, so 5 is deleted. Input: 2 -> 4 -> 6 -> 8 -> 33 -> 67 -> NULL Output: 2 -> 4 -> 6 -> 8 -> 33 -> NULL Explanation: The last node of the linked list is 67, so 67 is deleted.Recommended: Please try your approach on {IDE} first, before moving on to the solution.
Approach: To delete the last node of a linked list, find the second last node and make the next pointer of that node null.
Algorithm:
1. If the first node is null or there is only one node, then they return null.
if headNode == null then return null if headNode.nextNode == null then free head and return null2. Create an extra space secondLast, and traverse the linked list till the second last node.
while secondLast.nextNode.nextNode != null secondLast = secondLast.nextNode3. delete the last node, i.e. the next node of the second last node delete[secondLast.nextNode], and set the value of the next second-last node to null.
Implementation:
C++
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// CPP program to remove last node of // linked list. #include using namespace std; /* Link list node */ struct Node { int data; struct Node* next; }; /* Function to remove the last node of the linked list */ Node* removeLastNode[struct Node* head] { if [head == NULL] return NULL; if [head->next == NULL] { delete head; return NULL; } // Find the second last node Node* second_last = head; while [second_last->next->next != NULL] second_last = second_last->next; // Delete last node delete [second_last->next]; // Change next of second last second_last->next = NULL; return head; } // Function to push node at head void push[struct Node** head_ref, int new_data] { struct Node* new_node = new Node; new_node->data = new_data; new_node->next = [*head_ref]; [*head_ref] = new_node; } // Driver code int main[] { /* Start with the empty list */ Node* head = NULL; /* Use push[] function to construct the below list 8 -> 23 -> 11 -> 29 -> 12 */ push[&head, 12]; push[&head, 29]; push[&head, 11]; push[&head, 23]; push[&head, 8]; head = removeLastNode[head]; for [Node* temp = head; temp != NULL; temp = temp->next] cout data next, cur = cur->next] until cur->next is NULL. Read also: Delete any node from a linked list. Read also: Delete the first node of a linked list. Video liên quanChủ Đề |