Full Circle

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

Domain

Python

Difficulty

medium

Seniority

L3

Problem

A linked sequence is stored as a flat array `next_indices`: the value in each slot is the index of the next slot to visit, or -1 to mark the end. Starting from slot 0 and following these pointers, report whether the walk ever returns to a slot it has already visited. A pointer of -1, or one that falls outside the array, ends the walk rather than closing a loop.

Summary

Follow the chain long enough and it might loop back.

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