Implement tac (Reverse cat) with Progressive Optimisation

Problem Overview

Implement tac, the reverse of cat: given a file, print its lines starting from the last line and ending with the first. Once the simplest version works, the interviewer keeps asking you to optimise it: 1. Reduce the extra space to O(1). 2. Then, setting space and time complexity aside,…

• 2 candidate-reported follow-ups — the exact probes interviewers asked, with the trigger for each
• The rest of the problem statement — full requirements, constraints, and edge cases
• Approach and trade-offs — what passing candidates did, and the mistakes that sink people