Familiar Ground

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

Domain

Python

Difficulty

medium

Seniority

L3

Problem

A linked list is stored compactly as an array where `next_pointers[i]` holds the index of node `i`'s successor, or `-1` when node `i` is the tail. Starting at index 0 and following these pointers, return whether the walk ever returns to a node it already visited instead of terminating. A pointer that lands outside the array counts as a terminating tail, the same as `-1`.

Summary

Keep walking. Sooner or later you may recognize where you're standing.

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