## Round 1 - Coding ## Problem You are building a chat application. Given a list of messages, each with a UTC timestamp in ISO-8601 format and a target timezone offset (in hours, e.g. `-5` for EST), return the messages formatted for display with a human-readable local time. Group consecutive messages sent within the same minute under one timestamp header. ```python def format_messages( messages: list[dict], # [{"text": str, "utc_ts": str}] tz_offset: int ) -> list[str]: # Returns display strings; shared-minute messages share one header pass ``` ## Example ``` Input: messages = [ {"text": "Hey", "utc_ts": "2024-03-01T14:00:30Z"}, {"text": "Yo!", "utc_ts": "2024-03-01T14:00:55Z"}, {"text": "Later", "utc_ts": "2024-03-01T14:02:10Z"} ] tz_offset = -5 Output: ["[09:00 AM]", "Hey", "Yo!", "[09:02 AM]", "Later"] ``` ## Follow-ups 1. How do you handle DST transitions — where tz_offset itself changes mid-day? 2. What if messages arrive out of order? Should the grouping still work correctly? 3. How would you display relative times ("2 minutes ago") that update without a page refresh? 4. How do you localize AM/PM notation for locales that use 24-hour format?

InterviewDB Experience

Message Time - Parse and Format Chat Timestamps Across Time Zones

phone

Interview Experience

Round 1 - Coding Problem You are building a chat application. Given a list of messages, each with a UTC timestamp in ISO-8601 format and a target timezone offset (in hours, e.g. -5 for EST), return the messages formatted for display with a human-readable local time. Group consecutive messages sent within the same minute under one timestamp header. Example Follow-ups How do you handle DST transitions — where tz_offset itself changes mid-day? What if messages arrive out of order? Should the groupi…

Full Details

🔒

Unlock all Qrt questions

Full insider details, leaked discussions, and candidate experiences.

Get full access — $100 a year, unlimited access

About This Question

This is a candidate experience report from a qrt interview during the phone round.

It covers the following topics: Coding, Phone, Onsite, Strings .

Topics

Coding Phone Onsite Strings

Message Time - Parse and Format Chat Timestamps Across Time Zones

Interview Experience

Full Details

About This Question

Topics

More Qrt Interview Questions