The Elevator Trace

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

Domain

Python

Difficulty

medium

Seniority

L3

Problem

Given a list of lists (floors), concatenate all inner lists left-to-right to form the forward path; then append the reverse of that same concatenation. Return the full traversal list.

Summary

Nested floors. One path through.

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