Remove first node of the linked list
Given a linked list, the task is to remove the first node of the linked list and update the head pointer of the linked list.
Examples:
To remove first node, we need to make second node as head and delete memory allocated for first node.
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// CPP program to remove first node of
// linked list.
#include
using namespace std;
/* Link list node */
struct Node {
int data;
struct Node* next;
};
/* Function to remove the first node
of the linked list */
Node* removeFirstNode[struct Node* head]
{
if [head == NULL]
return NULL;
// Move the head pointer to the next node
Node* temp = head;
head = head->next;
delete temp;
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 = removeFirstNode[head];
for [Node* temp = head; temp != NULL; temp = temp->next]
cout data 23 -> 11 -> 29 -> 12
head = push[head, 12]
head = push[head, 29]
head = push[head, 11]
head = push[head, 23]
head = push[head, 8]
head = removeFirstNode[head]
while[head]:
print["{} ".format[head.data], end =""]
head = head.next
# This code is Contributed by Vikash Kumar 37
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// C# program to remove first node of
// linked list.
using System;
class GFG
{
// Link list node /
public class Node
{
public int data;
public Node next;
};
// Function to remove the first node
// of the linked list /
static Node removeFirstNode[Node head]
{
if [head == null]
return null;
// Move the head pointer to the next node
Node temp = head;
head = head.next;
return head;
}
// Function to push node at head
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;
}
// Driver code
public static void Main[String []args]
{
// Start with the empty list /
Node head = null;
// Use push[] function to con
// the below list 8 . 23 . 11 . 29 . 12 /
head = push[head, 12];
head = push[head, 29];
head = push[head, 11];
head = push[head, 23];
head = push[head, 8];
head = removeFirstNode[head];
for [Node temp = head; temp != null; temp = temp.next]
Console.Write[temp.data + " "];
}
}
/* This code contributed by PrinciRaj1992 */
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// javascript program to remove first node of
// linked list.
// Link list node /
class Node {
constructor[val] {
this.data = val;
this.next = null;
}
}
// Function to remove the first node
// of the linked list /
function removeFirstNode[ head] {
if [head == null]
return null;
// Move the head pointer to the next node
temp = head;
head = head.next;
return head;
}
// Function to push node at head
function push[ head_ref , new_data] {
new_node = new Node[];
new_node.data = new_data;
new_node.next = [head_ref];
[head_ref] = new_node;
return head_ref;
}
// Driver code
// Start with the empty list /
head = null;
// Use push[] function to con
// the below list 8 . 23 . 11 . 29 . 12 /
head = push[head, 12];
head = push[head, 29];
head = push[head, 11];
head = push[head, 23];
head = push[head, 8];
head = removeFirstNode[head];
for [ temp = head; temp != null; temp = temp.next]
document.write[temp.data + " "];
// This code is contributed by todaysgaurav
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Time complexity : O[1]
Delete a node in a Doubly Linked List
Pre-requisite: Doubly Link List Set 1| Introduction and Insertion
Write a function to delete a given node in a doubly-linked list.
Original Doubly Linked List
Singly Linked List vs Doubly Linked List
Before looking at the differences between the singly linked list and doubly linked list, we first understand what is singly linked list and doubly linked list separately.
What is the space complexity for deleting a linked list O'n O 1 either O 1 or O N?
Table of Contents
- What is the space complexity for deleting a linked list O'n O 1 either O 1 or O N?
- What is space complexity of linked list?
- What's the time complexity of removing an element from a doubly-linked list?
- What is the the best case time complexity of deleting a node in a singly linked list?
- What is the time complexity of removing the first element of a linked list?
- What is the complexity of removing the minimum item from a sorted linked list?
- Why are linked lists useful?
- What is the complexity of removing the maximum item from a sorted linked list?
- How to calculate time complexity of deletion in linked list?
- What is the time complexity of insertion in linked list?
- Which is more efficient filtering or deleting a linked list?
- What happens at the end of a singly linked list?
What is the space complexity for deleting a linked list O'n O 1 either O 1 or O N?
Discussion Forum
| b. | O[n] |
| c. | Either O[1] or O[n] |
| d. | O[logn] |
| Answer:O[1] |
What is space complexity of linked list?
Space. Linked lists hold two main pieces of information [the value and pointer] per node. This means that the amount of data stored increases linearly with the number of nodes in the list. Therefore, the space complexity of the linked list is linear: Space - O[n] .
What's the time complexity of removing an element from a doubly-linked list?
The time complexity for removal is only O[1] for a doubly-linked list if you already have a reference to the node you want to remove. Removal for a singly-linked list is only O[1] if you already have references to the node you want to remove and the one before.
What is the the best case time complexity of deleting a node in a singly linked list?
What is the best case time complexity of deleting a node in a Singly Linked list? Explanation: Deletion of the head node in the linked list is taken as the best case. The successor of the head node is changed to head and deletes the predecessor of the newly assigned head node. This process completes in O[1] time.
What is the time complexity of removing the first element of a linked list?
If you want to delete a specific element, the time complexity is O[n] [where n is the number of elements] because you have to find the element first. If you want to delete an element at a specific index i , the time complexity is O[i] because you have to follow the links from the beginning.
What is the complexity of removing the minimum item from a sorted linked list?
2 Answers. It is O[n], because after removing the element, all other elements need to be moved 1 place to the left. If you would have a Linked List, this would not be necessary, so for this data structure it would be O[1].
Why are linked lists useful?
Linked lists are useful because they support the efficient insertion and removal of elements at the expense of inefficient element access, as opposed to arrays. When a variable is created, the computer must allocate memory.
What is the complexity of removing the maximum item from a sorted linked list?
The time complexity for removal is only O[1] for a doubly-linked list if you already have a reference to the node you want to remove. Removal for a singly-linked list is only O[1] if you already have references to the node you want to remove and the one before.
How to calculate time complexity of deletion in linked list?
1.If pointer is given in this case Time Complexity is O [1]. 2.You DON'T have pointer to the node to be deleted [Search and Delete]. In this case Time Complexity is O [n]. I might be wrong, but for your first point, you would need a pointer to the node before the one you're deleting, not the one you're deleting. – MarkB Sep 29 at 8:16
What is the time complexity of insertion in linked list?
The time complexity of insertion is only O[1] if you already have a reference to the node you want to insert after. The time complexity for removal is only O[1] for a doubly-linked list if you already have a reference to the node you want to remove.
Which is more efficient filtering or deleting a linked list?
This means for example that filtering a linked list is more efficient than filtering a list based on an array. Your are correct. 1.If pointer is given in this case Time Complexity is O [1]. 2.You DON'T have pointer to the node to be deleted [Search and Delete]. In this case Time Complexity is O [n].
What happens at the end of a singly linked list?
Once you reach the end of the list, setNext of ‘temp’ to null, ‘cur’ is not being pointed to by any node, and hence it is available for garbage collection. 5. What is the functionality of the following code?