Paytm Senior Software Engineer Interview Experience

Given an array, maximize the number of segments (chunks) such that after sorting each chunk and concatenating, the result is sorted. Use a monotonically increasing stack. **Follow-ups**: Consider caching, observability, and sharding.

Given an array of policy names with Roman numeral suffixes (e.g., ['MAX_BUPA_IX', 'ICICI_LOMBARD_XIX']), sort them by the integer value of the Roman numeral first, then alphabetically. **Approach**: Parse Roman numerals into integers using a HashMap, create pairs of {policyName : number}, and sort these entries using a custom Comparator and lambda (first by value, then by key).

Design a file upload service similar to Dropbox. Your design should include distributed object storage for files, pre-signed URLs for direct client uploads, and a database structure for files, metadata, and share lists. **Considerations**: Choose NoSQL for metadata and share lists to enhance scalability.

Find the longest zigzag path in a binary tree. A zigzag path is defined as one where the direction alternates between left and right. **Approach**: Track the previous direction and current length. If the last move was to the left, the next must be to the right, and vice versa.

Design a Task Scheduler that can support one-time tasks and recurring tasks, with recurrence defined by cron expressions. **Approach**: Utilize ExecutorService, a Queue, and wait()/notify() for task coordination and execution. Consider how to apply the Strategy pattern so that different task types, especially those based on cron, can calculate their next execution independently.