How to handle huge inputs?

In a coding interview, after solving an in-memory algorithmic problem, the interviewer asks: "What would you do if the input were extremely large?"

Give a structured answer that explains how to reason from constraints to design choices.

Constraints & Assumptions

• The original problem could be common, such as interval scheduling, grouping, counting, or sorting.
• The follow-up is general rather than tied to one exact algorithm.
• Discuss exact versus approximate answers, memory limits, streaming, chunking, external storage, and distributed processing.
• Do not jump straight to "use distributed systems" without explaining why.

Clarifying Questions to Ask

• Does the full input fit in memory?
• Is the input static, streamed, or continuously updated?
• Do we need an exact answer or is approximation acceptable?
• Do we need global ordering, random access, or only a summary?
• Are we constrained by memory, disk I/O, network, latency, or throughput?
• Is this single-machine or multi-machine?