Given a singly linked list and a position, delete a linked list node at the given position.
Example:
Input: position = 1, Linked List = 8->2->3->1->7 Output: Linked List = 8->3->1->7 Input: position = 0, Linked List = 8->2->3->1->7 Output: Linked List = 2->3->1->7
If the node to be deleted is the root, simply delete it. To delete a middle node, we must have a pointer to the node previous to the node to be deleted. So if positions are not zero, we run a loop position-1 times and get a pointer to the previous node.
Below is the implementation of the above idea.
Javascript
<script>// A complete working javascript program to // delete a node in a linked list at a // given position// head of listvar head; /* Linked list Node */class Node { constructor(val) { this.data = val; this.next = null; }}/* Inserts a new Node at front of the list. */function push(new_data){ /* * 1 & 2: Allocate the Node & Put in the data */ var new_node = new Node(new_data); /* 3. Make next of new Node as head */ new_node.next = head; /* 4. Move the head to point to new Node */ head = new_node;}/* * Given a reference (pointer to pointer) to the * head of a list and a position, * deletes the node at the given position */function deleteNode(position){ // If linked list is empty if (head == null) return; // Store head node var temp = head; // If head needs to be removed if (position == 0) { // Change head head = temp.next; return; } // Find previous node of the node to be deleted for(i = 0; temp != null && i < position - 1; i++) temp = temp.next; // If position is more than number of nodes if (temp == null || temp.next == null) return; // Node temp->next is the node to be deleted // Store pointer to the next of node to be deleted var next = temp.next.next; // Unlink the deleted node from list temp.next = next; }/** This function prints contents of linked * list starting from the given node*/function printList(){ var tnode = head; while (tnode != null) { document.write(tnode.data + " "); tnode = tnode.next; }}/** Driver program to test above functions.* Ideally this function should be in a* separate user class. It is kept here * to keep code compact*//* Start with the empty list */push(7);push(1);push(3);push(2);push(8);document.write("Created Linked list is: <br/>");printList();// Delete node at position 4deleteNode(4); document.write("<br/>Linked List after " + "Deletion at position 4: <br/>");printList();// This code is contributed by todaysgaurav</script> |
Output:
Created Linked List: 8 2 3 1 7 Linked List after Deletion at position 4: 8 2 3 1
Time Complexity: O(n), where n represents the length of the given linked list.
Auxiliary Space: O(1), no extra space is required, so it is a constant.
Please refer complete article on Delete a Linked List node at a given position for more details!
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