APT Portfolio Interview Experience - Junior/middle C++ developer
Interview Experience
I was contacted by an external headhunter company (which specializes in trading recruiting) for the opportunity of junior/middle C++ developer in Amsterdam. First, we had ...
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I was contacted by an external headhunter company (which specializes in trading recruiting) for the opportunity of junior/middle C++ developer in Amsterdam. First, we had a general conversation about the position, company, requirements, etc. After that, I've sent my CV and received a link to HackerRank test. There were 4 problems. I would say all of them medium-hard on leetcode. I remember only 2 of them: Network packets coming to the client, some of them might be out of order. You have to implement a function which accepts packets and write them to the std::cout in the correct order on the fly. Some problems for the disjoint set union. The solution is quite straightforward if you're familiar with DSU. I got a response quite quickly, and they invited me to the interview. Interview with Senior Developer: 1-hour interviewed by a senior dev. A lot of questions about my experience. Focusing on my previous C++ projects, what optimizations did we do, what tools did we use, C++ features, etc. CPU architecture. Its main components and how they work - alu, cu, ram, virtual memory, tlb. How a multicore system share cache. What's speculative execution and branch prediction. C++ questions: virtual functions, templates, SFINAE, template functions, enable_if. No live coding part here. Interview with Project LeadL: Questions about operating system - why we need kernel and user mode, why system calls are slow, what is interrupt, what happens during an interrupt. Also a lot of questions about my experience. Interview with CTO (final): Several questions about my motivation in this role, behavioural questions, again my experience. I didn't remember well technical questions, some of them: If you would implement a driver for an external computing device, how would you implement data exchange (in case speed is the main priority) The naive implementation of memcpy. How would you optimize it? void my_memcpy(char from, char to, int count) { for (int i = 0; i < count; i++) { to[i] = from[i]; } } My answer: unwind loop and use SSE instructions. In the end, I asked a couple of questions about the company. Results: After 3 days of waiting I contacted my headhunter from an external company, he said no decision yet, it should be next week. Next week I sent an email again, but didn't get a response in 2 days and called him on mobile. He said the APT is having another candidate interview and I should wait more, " no worries, they were positive about you ". On 3rd week he was completely ignoring my emails. I emailed APT's HR directly. Her words " no decision yet " started freaking me out. After more than a month of waiting, I texted HR again and she answered that unfortunately, they decided not to go with my candidacy. No feedback, no explanations, nothing. I asked for the feedback - what went well and what didn't. They agree to compose it but didn't do... The entire process lasted for around 3 months. As a result, many hours were spent on it but no feedback received. Poor interview experience.
About This Question
This is a candidate experience report from a apt portfolio interview for a quant role (junior level) during the oa round reported in 2020.
It covers the following topics: Os, Union Find .
Difficulty rating: Easy
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About Apt Portfolio Interview Reports
This question was reported by a candidate who interviewed at Apt Portfolio. LeakCode aggregates interview reports from 10+ sources, including 1Point3Acres, Glassdoor, LeetCode Discuss, Blind, Reddit, Indeed, and Nowcoder. Each report is translated where necessary, deduplicated against existing entries, and tagged by company, role, round type, and reporting date.
Use this question as one calibration data point, not a memorization target. Companies typically rotate their question pools every 2-4 months; the exact wording of a 2024 question may differ from what you encounter today. The underlying pattern, difficulty level, and follow-up depth at Apt Portfolio are the higher-signal extractions to take from this report.
For broader preparation context, the Apt Portfolio interview process typically includes a recruiter screen, one or two technical phone screens, and a 4-5 round on-site loop covering coding, system design (at L4+ levels), and behavioral. Reports tagged on LeakCode show the round-by-round distribution and typical difficulty calibration. To browse questions filtered by round type and seniority, use the company hub linked above.
How To Practice This Type of Question
Solve similar problems on LeetCode under timed conditions (25-35 minutes per medium difficulty). The goal is pattern recognition: recognize the underlying technique (sliding window, two-pointer, BFS, memoized recursion, etc.) within 60-90 seconds of reading. Strong candidates verbalize their hypothesis out loud before coding, then iterate based on feedback. Weak candidates dive into implementation immediately, lose time on the wrong approach, and run out of time for follow-ups.
Companies update their question pools every 2-4 months. The exact wording of any given question may have been retired by the time you interview. Focus your prep on the pattern, not the specific problem. The patterns that appear in Apt Portfolio reports consistently are the ones worth investing in; one-off niche problems are not.
During Your Apt Portfolio Round
Apply the standard interview round template: clarify requirements (2-3 minutes), state your approach out loud and confirm direction with the interviewer (3-5 minutes), code with narration (15-25 minutes), test with concrete examples including edge cases (5 minutes), discuss optimization or trade-offs if time permits (5 minutes). This template is universally accepted across FAANG and adjacent companies; deviating from it produces weaker interviewer feedback signal.
The single most predictive failure mode in Apt Portfolio reports tagged "no hire": not asking clarifying questions. Interviewers are explicitly trained to weight this. Strong candidates ask 3-5 clarifying questions even on problems that look obvious; weak candidates dive into code immediately. The clarifying-question check is often the first signal recorded in the interviewer's written notes.