Subscription Email Scheduler

Problem Overview

Implement a subscription email notification system. You are given two primary inputs: 1. send_schedule (dict/map): Maps event keys to email subject/title strings. Keys include "start" (maps to e.g. "Welcome"), "end" (maps to e.g. "Expired"), and one or more negative integers (e.g. -15 maps to "Upcoming Expiry") representing days before expiration.…

• 5 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