Just ended recently Apple Frontend Engineer This round of technical aspects mainly revolves around Coding + Behavioral. System Design does not appear, but this does not mean that Apple will not take the test - many candidates will only meet in subsequent rounds, so do not relax when preparing. The following is a direct review of the core content to provide some reference for students who are preparing for Apple interviews.
Coding interview questions review
There is only one core algorithm question in this round, but the restrictions are very critical.
The general idea of the question is: given an integer array of approximately 75 elements, it is necessary to deduplicate the array and sort the results. The requirement for deduplication is that if an element appears repeatedly in the array, the duplicate value needs to be zeroed out (such as set to 0 or marked for removal). At the same time, it is clearly stipulated that no native sorting functions can be used, including sort, quicksort, etc.
At first glance, N is very small, and you can pass it by just writing a bubble sort. However, the interviewer emphasized from the beginning that this question should not just consider "can it run", but should give a reasonable explanation from the perspective of complexity.
Overall idea of problem solving
During the interview, I split the problem into two stages to think about: first deal with deduplication, and then deal with sorting. The interviewer recognizes this dismantling method and will continue to follow your line of thinking.
In the deduplication stage, a more straightforward approach is to use a Hash Set to record elements that have already appeared. When traversing the array, if the current element has already appeared in the Set, the position will be zeroed out; if it has not appeared before, the element will be added to the Set. In this way, duplication can be completed in one scan, the time complexity is O(N), and the logic is very clear.
The interviewer will be more concerned about two points at this stage: first, whether the definition of zero out will affect subsequent sorting; second, whether 0 itself may be legal data. If you can take the initiative to mention these edge cases and explain how you handle them, it will be a clear bonus. After completing the deduplication, the next step is the sorting problem. Since the use of native sorting functions is prohibited, it essentially tests whether you truly understand the sorting algorithm, rather than just adjusting the library.
What I chose at the time was handwritten merge sort. The reason is also very simple: the time complexity is stable at O(N log N), the implementation logic is clear, and boundary bugs are not easy to occur in interview scenarios. It will also be easier for the interviewer to follow your recursive logic instead of repeatedly interrupting on details.
Hide bonus points
During the sorting stage, the interviewer asked: "If I told you that the number range in the array is very small, such as 0 to 100, how would you optimize it?"
This is a very typical Apple question.
Under this premise, you can actually use counting sorting directly. By counting the number of occurrences of each number through a fixed-size counting array, and then backfilling the results in order, the overall time complexity can be O(N). If you can realize that this is a scenario that can be optimized using data distribution characteristics, the interviewer will generally give very positive feedback.
Essentially, the test here is not how many algorithms you have memorized, but whether you have the ability to adjust the solution based on the "input characteristics".
Behavioral Interview Review
This round of BQ is a very common type for Apple, but it is not easy to answer well. The key question is Most Proud Project, which asks you to talk about a project experience that you are most proud of.
What the interviewer really wants to examine is not how complex the project itself is, but whether you have a clear understanding of what you have done and whether you truly understand the value of the project. When answering, you must be careful not to always use "what our team did", but to highlight "what I specifically did." Especially personal contributions in technology selection, key decisions, performance optimization or problem solving.
I personally highly recommend using the STAR principle to organize language, but don’t use rigid templates. The key point is to explain the Result clearly, and it is best to use data to quantify the results, such as performance improvement ratio, error rate reduction, user experience improvement effect, etc.
A little additional explanation
We usually compile a lot of interview questions and questioning routines from real first-tier companies such as Apple, Meta, Google, etc., including coding questions like this that look simple but require basic skills. Want to master high-frequency question types and sort out the answer framework in advance, or need it in actual combat Interview assistance You can contact us. If you are the kind of person who is generally familiar with the types of questions but prone to making mistakes under interview pressure, you can give yourself an extra layer of insurance. The better prepared you are, the more stable your on-site performance will be. This is especially obvious in Apple interviews.
