Detect Loop in Singly Linked List

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

Explanation:

A cycle in a linked list occurs when a node's next points back to a previous node in the list, creating a loop.

For this problem, there is no partial marking; all test cases must be accurately handled.

Input:

The first line of each test case contains the elements of the singly linked list separated by a single space and terminated by -1 (which is not a valid list element).
The second line contains an integer "pos" indicating the 0-indexed position in the linked list where the tail connects. If "pos" is -1, the linked list has no cycle.

Output:

Output 'true' if the linked list has a cycle, or 'false' otherwise.
Explicit printing is not required; it is managed for you.

Example:

Input: [3, 2, 0, -4, -1], pos = 1
Output: true

Constraints:

• 0 <= N <= 10⁶
• -1 <= pos < N
• -10⁹ <= data <= 10⁹ and data ≠ -1
• Time Limit: 1 sec

Note:

Try to solve this problem in O(N) Time Complexity and O(1) Space Complexity.