Google Interview Process
Google interviews typically consist of four or five rounds, all conducted on the same day, which makes for a pretty intense experience. The first round is a 30-minute behavioral interview, followed by several 45-minute technical interviews.
The online assessment and behavioral questions at Google are usually quite standard. They mainly assess your diversity and communication skills. You can generally prepare for these by using the STAR method (Situation, Task, Action, Result), which is widely discussed online.
Technical Interview
My impression is that Google interviews emphasize your problem-solving approach and thought process. Often, they won’t run your code, so minor compilation errors aren’t a huge deal. Interviewers are much more interested in seeing your solid computer science fundamentals and capabilities.
You typically won’t encounter overly obscure algorithm problems. However, interviews often feature many detailed corner cases and various ‘if’ conditions.
Communication and Understanding
Your communication and comprehension skills are also crucial. When you encounter a problem, do you take the time to clarify the input and output formats, various details, and data ranges? Before you even start coding, it’s best to discuss your ideas with the interviewer and get their approval. Also, as you’re writing code, it’s a good practice to explain your thought process aloud, allowing the interviewer to easily follow and approve of your algorithm.
Technical Interview Structure
The later technical rounds are the most important. Usually, the interviewer will start with a brief self-introduction, then ask the interviewee to do the same. After that, the interviewer will give you a relatively straightforward problem that you should try to complete within 20 minutes. This is because the last ten minutes might involve a follow-up question, which could be an optimization problem discussed verbally or requiring minor code changes.
Key Areas
Google’s technical interviews for engineering roles primarily focus on the following areas. Candidates should prepare by solving problems, seeking advice from those with interview experience, doing mock interviews, and even getting assistance with phone screen interviews. Without understanding the interview’s direction, first-time interviewees can easily underperform and miss out on an offer.
- Coding: You’ll be asked to implement given problems using a programming language you’re comfortable with (any language is fine). The interview will heavily emphasize your understanding and communication skills throughout the problem-solving process.
- Algorithms: This covers sorting, searching, divide and conquer, dynamic programming, greedy algorithms, recursion, and specific data structures. You might also encounter algorithms like Dijkstra’s and A*. You’ll need to be proficient in analyzing algorithm complexity.
- Sorting: Expect questions on common sorting algorithms and their time/space complexity, such as Quick Sort, Merge Sort, Heap Sort, Insertion Sort, and Radix Sort.
- Data Structures: Familiarity with arrays, linked lists, heaps, stacks, hash tables, trees, and binary trees is essential.
- Math: You might encounter questions related to discrete mathematics and combinatorics, for example, methods for choosing k items from N.
- Graphs: Be prepared for questions on graph representations (like adjacency matrices or adjacency lists) and algorithms such as Breadth-First Search (BFS) and Depth-First Search (DFS).
- Recursion: Understanding the conversion between recursive and iterative solutions is important.
- Other: This category can include topics like system design and operating systems concepts.
Google Interview Differences: China vs. US
While it’s true that interviews outside of China tend to be a bit simpler than those within China, the difference isn’t drastic – I’ve experienced both. China’s tech scene is notoriously competitive, or “卷” (rolled up), which contributes to the intensity.
However, there’s one consistent hurdle: the Community Review. This is the final stage where code written by candidates worldwide gets reviewed by the US headquarters. The standards for this round are identical globally.
The Interviewer’s Influence
For the initial 3 to 5 technical rounds, the interviewer plays the biggest role. Although Google does have its question bank, most problems are sourced or created by the interviewers themselves. Some might pose challenging questions, and if you crack them, you’ll likely get a strong evaluation. Others might offer simpler problems, but these often come with two follow-up questions, escalating in difficulty.
Honestly, a good algorithms course can probably solve 99% of these problems (because no one can promise 100%). When it comes to landing a role, the interviewer’s preference for a candidate accounts for at least a third of the decision. This is something you’ll gradually come to understand through experience. It’s a mix of luck and a bit of interpersonal skill – your demeanor, appearance, and communication. The rest, of course, is pure ability.