Here is the interview question prompt, presented for reference.

What is the best way to find out if a linked list contains a loop? You're given the following data structure as the definition of a linked list node:

class LinkedListNode {
    constructor(val) {
        this.val = val;
        this.next = null;
    }
}

A loop or a cycle in graph theory is a path of nodes and edges where a node is reachable from itself.

Implement a detectLoop method that takes a linked list head node as the parameter and returns true or false depending on whether there's a cycle.

Constraints

• Length of the linked list <= 10000
• Value stored in each node will be between -1000000000 and 1000000000
• Expected time complexity : O(n)
• Expected space complexity : O(1)

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