Google Coding Interview Questions 2025

Google Coding Interview Questions: A Comprehensive Guide for 2025​

Preparing for Google’s coding interviews requires a deep understanding of data structures, algorithms, and problem-solving techniques. This guide covers essential topics, real examples, and the interview process to help you succeed. Whether you’re targeting internships or full-time roles, mastering these elements is critical to standing out in one of the most competitive hiring processes in the tech industry.

Google Coding Interview Process

1. ​Initial Screening (Phone/Online Assessment)

   • Candidates often start with a 45-minute technical phone interview or an online coding challenge.
   • Example question: “Find the K closest numbers to X in a sorted array” or “Check if a binary tree is a valid BST.”
   • Focus: Evaluate basic coding skills, algorithmic thinking, and clarity in communication.

2. ​Onsite Interviews (4–5 Rounds)

   • ​Technical Coding Rounds:
     • Solve 1–2 medium-to-hard problems per round, such as dynamic programming, graph traversal, or string manipulation.
     • Example: “Design an LRU cache” or “Determine if a string can be segmented into dictionary words.”
   • ​System Design Round​ (for mid/senior roles):
     • Design scalable systems (e.g., “Build a simplified AWS S3 storage system”).
   • ​Behavioral/Cultural Fit Round:
     • Discuss past projects, teamwork, and alignment with Google’s values.

3. ​Final Hiring Committee Review

   • Interview feedback is reviewed holistically. Google emphasizes “technical depth” and problem-solving consistency.

​Common Google Coding Interview Questions

Below are frequently asked question categories with examples:

1. ​Arrays & Strings​

   • Easy: “Check if two strings are k-anagrams.”
   • Medium: “Find the smallest window in a string containing all characters of another string.”

2. ​Linked Lists & Trees​

   • Medium: “Delete a node with a given key in a linked list.”
   • Hard: “Check if a binary tree contains duplicate subtrees of size 2 or more.”

3. ​Dynamic Programming​

   • Medium: “Boolean Parenthesization” (count ways to parenthesize an expression to return true).
   • Hard: “Closest Palindrome” (find the nearest palindrome for a numeric string).

4. ​Heap & Priority Queue​

   • Medium: “Merge K sorted linked lists.”
   • Example from Google’s intern笔试: “Allocate lockers using a min-heap to track the smallest available number.”

5. ​**System Design (Mid/Senior Roles)**​

   • Example: “Design a distributed file storage system” or “Optimize API rate limiting for Google Maps.”

​Preparation Tips​

1. ​Master Core Algorithms​
   • Prioritize topics like binary search, BFS/DFS, and sliding window. Use platforms like LeetCode and HackerRank.
2. ​Practice Google-Style Problems​
   • Google often uses custom scenarios (e.g., “Design a maze generation algorithm”). Practice translating abstract problems into code.
3. ​Optimize Communication​
   • Verbally explain your thought process during coding. Interviewers assess clarity and collaboration.
4. ​Build Projects​
   • Highlight impactful projects (e.g., “Developed a React Native finance app”). Google values initiative and real-world application.

​Why Google’s Interviews Are Unique​

• ​Coding-Only Focus: Recent trends show extended coding rounds (e.g., 3-hour sessions with 7+ problems).
• ​No “Lifetime Limit”​: Contrary to myths, Google allows reapplication after 6–12 months if initial attempts fail.

Google Coding Interview Questions: A Comprehensive Guide for 2025​
By focusing on structured practice, clear communication, and system design fundamentals, you’ll be well-prepared to tackle Google’s rigorous interviews. Stay updated with evolving trends, and leverage resources like Cracking the Coding Interview and mock interviews to refine your skills.