Footprints in the Feed

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

Domain

Python

Difficulty

medium

Seniority

L4

Problem

You're rolling up raw feed-handler log lines in `lines`, each a CSV row of `date,process,host,log_message,bytes`, where the `process` name carries the exchange as its leading token (so `nyse_feed_handler` is an NYSE process and `nasdaq_market_data` is a NASDAQ one). Roll the byte counts up two ways in one pass: total bytes per day, and total bytes per exchange within each day. Return both rollups together, the per-day totals first.

Summary

Every trade left a footprint.

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