Google Interview Prep
Google Coding Interview
How the coding round works at Google: Medium-to-hard DSA, often with a follow-up twist. Optimality and complexity analysis matter a lot.
Start a free Google coding mockWhat this round tests
- Data structures and algorithms
- Pattern recognition (two pointers, BFS/DFS, DP, etc.)
- Edge-case handling
- Clean, correct code and complexity analysis
How to prepare for Google's coding round
- Master the core patterns rather than memorizing problems.
- Practice talking through your approach before coding.
- Always state time and space complexity.
- Do timed problems in a real editor and run against tests.
Sample questions
- Find the number of islands in a 2D grid, then extend it to count distinct island shapes.
- Given a dictionary, find the longest word built one character at a time from other words.
- Two Sum and its variants (three sum, k-sum).
- Find the number of islands in a grid (BFS/DFS).
- Longest substring without repeating characters (sliding window).
FAQ
Does Google have a coding round?
Yes. In the Google loop this shows up as "Coding (x2-3)": Medium-to-hard DSA, often with a follow-up twist. Optimality and complexity analysis matter a lot.
How many problems should I practice?
Quality over quantity — deeply understanding ~150 problems across the core patterns beats grinding 500 shallowly. The goal is to recognize the pattern, not recall the exact problem.
Should I talk while coding?
Yes. Interviewers score communication. Narrate your approach, tradeoffs, and edge cases as you go — silent correct code scores worse than communicated correct code.
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