ListNode
is a simple data structure commonly used to create linked lists in JavaScript. A linked list is a linear data structure where each element (node) is a separate object. Each node consists of two main parts: the data and a reference (or link) to the next node in the sequence.
In the context of this problem, ListNode
represents a node in a singly-linked list. Each ListNode
object has two properties:
-
val
: Represents the value stored in the node. -
next
: Represents a reference to the next node in the linked list. It's initialized tonull
by default.
Here's the definition of ListNode
used in the addTwoNumbers
function:
function ListNode(val, next) {
this.val = (val === undefined ? 0 : val); // Value of the node
this.next = (next === undefined ? null : next); // Reference to the next node
}
Example:
Let's say you want to create a linked list with nodes containing values [2, 4, 3]
. You can do it like this:
const node1 = new ListNode(2); // Node with value 2 and next pointing to null
const node2 = new ListNode(4); // Node with value 4 and next pointing to null
const node3 = new ListNode(3); // Node with value 3 and next pointing to null
// Link the nodes together to form a linked list: 2 -> 4 -> 3
node1.next = node2;
node2.next = node3;
// Now, node1 represents the head of the linked list
In the addTwoNumbers
function, you'll often see linked lists represented and manipulated using these ListNode
objects. They provide a straightforward way to construct and traverse linked lists, making it easier to solve problems that involve linked list manipulation.
Disclaimer: This article was created with the help of AI.
Top comments (4)
Nice information in a simple way
I think its useful to understand what is the linked list.
Thank you.
Completely wrong!
there is nothing called ListNode in JS .
you have to implement one to use it.
What you are demonstrating is very specific to leetcode.
Well, as a built-in object in the Javascript interface, true, there is no ListNode object. That's because we don't really need one. Javascript developers don't operate at that low level. However, it does use linked lists as a part of constructing and manipulating Map objects, and thus it is helpful to understand what is happening under the hood.