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Coding/Arrays and strings

Linked list cycle start

Write codeMedium25 minAmazon and Microsoft style

Your task

A singly linked list is encoded as next_arr, where next_arr[i] is the index of the node that follows node i, or -1 if it is the tail. head is the starting node index (or -1 for an empty list). If the list contains a cycle, return the index of the node where the cycle begins; otherwise return -1. Solve in O(1) extra space.

Examples

cycle_entry(next_arr: list[int], head: int) -> int
Example 1
Inputcycle_entry([1, 2, 3, 1], 0)
Output1