Cycle Detection: Hare 🐇 and Tortoise 🐢

Example 1: head = [3, 2, 0, -4], pos = 1

ListNode slow = head, fast = head;
while (fast != null && fast.next != null) {
    slow = slow.next;
    fast = fast.next.next;
    if (slow == fast) {
        return true;
    }
}
return false;
Step: 0 / 0