You are given the head of a linked list. Determine whether the linked list has a cycle in it. There is a cycle in a linked list if there is some node in the list that can be reached again by continuously following the next pointer. Internally, pos is used to denote the index of the node that tail's next pointer is connected to. Note that pos is not passed as a parameter. Return true if there is a cycle in the linked list. Otherwise, return false. If a cycle exists, find the node where the cycle begins.

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Accepted Answer

To detect and remove a cycle from a linked list, we can use Floyd's Cycle Detection Algorithm.

Use two pointers, slow and fast, to detect a cycle in the linked list.
If there is a cycle, the fast pointer will eventually meet the slow pointer.
Once the cycle is detected, reset one of the pointers and move them at the same pace to find the start of the cycle.
Remove the cycle by setting the next pointer of the node where the two pointers meet to null.