Here is the interview question prompt, presented for reference.

You are given a `head`

of a linked list of length `n`

such that each node contains an additional `random`

pointer. This `random`

pointer may point to any other node in the list or is `null`

.

Create a `deep copy`

of the given linked list, and return its `head`

such that **no additional space** is used. The deep copy should consist of exactly `n`

brand new nodes. Each new node must have the following properties:
- Its value is set to the value of its corresponding original node.
- Both the `next`

and `random`

pointers of the new node should point to new nodes in the copied list, such that the pointers in the original list and copied list represent the same list state.
- None of the pointers in the new list should point to nodes in the original list.

![image](https://storage.googleapis.com/algodailyrandomassets/curriculum/linked-lists/clone-random-pointer-linked-list/problem.png)

For example, if there are two nodes X and Y in the original list, where `X.random --> Y`

, then for the corresponding two nodes `x`

and `y`

in the copied list, `x.random --> y`

.

## Constraints

`0 <= n <= 1000`

- 104 <= Node.val <= 104
`Node.random`

is `null`

or points to some node in the linked list.

You can see the full challenge with visuals at this link.

This is the main discussion thread generated for Clone Random Pointer Linked List (Main Thread).