Linked List Cycle Detection

Determine if a given singly linked list of integers forms a cycle.

Explanation:

A cycle in a linked list occurs when a node's next reference points back to a previous node in the list, transforming the structure from a linear layout into a loop.

Input:

The first line contains the elements of the singly linked list separated by a space, ending with -1 to indicate termination. 
The second line provides an integer "pos", the position (0-indexed) where the tail of the linked list connects back in the list. A "pos" value of -1 indicates there is no cycle.

Output:

Return 'true' if the linked list contains a cycle, otherwise return 'false'. The output handling is managed internally.

Example:

Input:
 3 2 0 -4 -1
 1
Output:
 true

Constraints:

• 0 <= N <= 10^6
• -1 <= pos < N
• -10^9 <= data <= 10^9 and data ≠ -1

Note: Attempt to solve this problem with O(N) time complexity and O(1) space complexity.