Agoda Staff Backend Interview Experience | 1-Day Fast Track

Round 1: Coding & Algorithms (60 min)

Q1: Degree of an Array https://leetcode.com/problems/degree-of-an-array/

Q2: Disk Space Analyzer Given an array space[] and window size x:

• Find the minimum available space in every contiguous window of size x
• Return the maximum among those minimum values Example: x = 2, space = [8, 2, 4, 6] window minimums = [2, 2, 4] answer = 4

Constraints were large, so an efficient sliding‑window approach, combined with Min‑heap was required. Managed to solve both questions before time.

Round 2 — Platform + Code Review (60 min)

This was the more interesting round. The initial architecture was roughly:

The Search Service calls multiple external vendors, aggregates their results, stores them, and returns the response. Search results remain valid for 1 hour.

Topics we discussed:

• Redis caching with 1‑hour TTL
• Cache key around (productId, vendorId)
• Database as a fallback/persistent store
• Separating vendor communication into a dedicated Vendor Service
• Handling many requests arriving together after cache expiry / cache stampede
• Distributed coordination using Redis
• DB indexing around product/vendor lookup
• Authentication and general service responsibilities

The interviewer also wanted to discuss testing, but we were running short on time.

Code Review I was given Java code implementing the same Search Service. There was vendor‑specific logic similar to:

if (vendor == A) {
    ...
} else if (vendor == B) {
    ...
} else if (vendor == C) {
    ...
}

I suggested extracting this behind a common interface using the Strategy Pattern, with separate vendor implementations. We also discussed:

• Single Responsibility Principle
• dependency injection
• maintainability/extensibility
• separation of vendor‑specific logic
• parallel vendor calls
• general readability/code structure

Outcome

Unfortunately, I was rejected after Round 2, so I didn't proceed to the Architecture and Hiring Manager rounds.

The coding round went well, and I felt I answered most of the Platform/code‑review questions reasonably well. My main takeaway is that for a Staff‑level Platform round, they may expect you to proactively identify bottlenecks and design issues.

Would be interested to hear from anyone who has interviewed for Agoda Staff/Senior Backend roles.