Detect Cycle in Sequence

A medium Python interview practice problem on DataDriven. Write and execute real python code with instant grading.

Domain

Python

Difficulty

medium

Seniority

L3

Problem

You are given a list of integers where each value at index i is the next index to visit (or -1 to terminate). Starting from index 0, follow the chain and return True if you revisit any index, False otherwise. Out-of-range indices (including -1) count as termination, not a cycle.

Summary

Follow the chain long enough and it might loop back.

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