System design
System design at L5 is one service deep-dive. At L6+, expect multi-service coordination with explicit capacity and latency numbers. Google scores capacity estimation more than most companies.
Google coding interview — the patterns you should actually drill.
TL;DR
Google's coding loop is typically 4–5 rounds of 45 minutes: two coding, one system design (L5+), one behavioral ('Googleyness and Leadership'), and one deep-dive on language fluency. Recruiters score each round on generalized axes rather than a hard rubric.
Top 5 patterns at Google
These patterns show up most often in publicly-reported Google loops. Master the first three before you move on.
- #1Graph BFS / DFS
Breadth-first for shortest unweighted paths; depth-first for exhaustive traversal.
- #2Dynamic Programming
Break an overlapping-subproblem problem into a recurrence and cache results.
- #3Sliding Window
Maintain a contiguous range and slide its boundaries to avoid recomputation.
- #4Two Pointers
Two cursors moving independently over a sorted or monotone structure.
- #5Heap & Priority Queue
A data structure that returns the min or max in O(log n) per operation.
Behavioral
Googleyness is a real rubric dimension — the interviewer is evaluating collaboration, comfort with ambiguity, and humility. Concrete stories beat abstract claims.
Google quirk
Google interviewers often push on 'can you make it faster' even when you've hit optimal — they want to see whether you know when you're done or invent premature optimizations.
Frequently asked questions
- What patterns does Google ask in coding interviews?
- Most-reported patterns in Google loops: Graph BFS / DFS, Dynamic Programming, Sliding Window, Two Pointers, Heap & Priority Queue. These 5 patterns cover the majority of the coding rounds.
- How long is a Google interview loop?
- Google's coding loop is typically 4–5 rounds of 45 minutes: two coding, one system design (L5+), one behavioral ('Googleyness and Leadership'), and one deep-dive on language fluency. Recruiters score each round on generalized axes rather than a hard rubric.
- What is unique about Google's interview?
- Google interviewers often push on 'can you make it faster' even when you've hit optimal — they want to see whether you know when you're done or invent premature optimizations.
- What does system design at Google look like?
- System design at L5 is one service deep-dive. At L6+, expect multi-service coordination with explicit capacity and latency numbers. Google scores capacity estimation more than most companies.
- How should I prepare behaviorally for Google?
- Googleyness is a real rubric dimension — the interviewer is evaluating collaboration, comfort with ambiguity, and humility. Concrete stories beat abstract claims.
- How many weeks of prep do I need for a Google onsite?
- Most candidates benefit from 8–12 weeks of structured prep: 4 weeks on pattern fluency, 4 weeks on timed practice, and 2–4 weeks on mock interviews and Google-specific topics.
Drill the Google pattern distribution.
Start with the diagnostic. We'll weight your loop toward the 5 patterns above.