Google Coding & Algorithms Interview Questions

Preparing for Google Coding & Algorithms interview questions means getting ready for a rigorous, process-driven evaluation that emphasizes clean problem solving, clear communication, and algorithmic depth. Google tends to focus on core data structures and algorithmic patterns—arrays and strings, trees and graphs, dynamic programming, hashing, and complexity trade-offs—while also assessing how you reason through edge cases, test your ideas, and write production-minded code in a collaborative environment. Expect live coding on a shared document during screens and multiple 45‑minute coding rounds in onsite or virtual loops, with system design and behavioral evaluations added for more senior roles. Effective interview preparation balances breadth and depth: practice medium-to-hard algorithmic problems under timed conditions, review core computer science fundamentals, and rehearse explaining tradeoffs and correctness aloud. Work on structured problem walkthroughs, mock interviews that simulate Google’s collaborative doc format, and concise post-solution optimizations. Also prepare concise, impact‑focused stories for the behavioral round and plan a realistic multi-week schedule that includes focused drills, full mock loops, and targeted review of persistent weak spots.

224 Questions 1 Company08.01.2026
Showing 20 results
Role
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Google
Easy
Software Engineer Locked

Busiest Rental Car

This question evaluates a candidate's ability to simulate a resource-allocation process using interval scheduling and greedy assignment rules. It test...

Coding & Algorithms
5
0
18 people solved
Jun 22, 2026
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Google
Medium
Software Engineer Locked

Boolean Expression Tree with Leaf Flips

This question evaluates a candidate's ability to work with tree data structures and apply efficient update propagation techniques. It tests practical ...

Coding & Algorithms
7
0
31 people solved
Jun 9, 2026
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Google
Medium
Software Engineer Locked

Assign meetings to rooms with delays

This question evaluates skill in scheduling algorithms, priority queue and heap usage, greedy decision-making, and time-based event simulation for man...

Coding & Algorithms
12
1
147 people solved
Jan 6, 2026
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Google
Hard
Software Engineer

Find maximum value in huge text file

You are given the path to a very large text file on disk. The file has the following properties: - Each line contains exactly one signed 64-bit intege...

Coding & Algorithms
31
0
225 people solved
Dec 8, 2025
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Google
Medium
Software Engineer

Build Prefix Lookup with a Trie

Build prefix lookup for repeated queries. Given words and query prefixes, return matching words for each query in lexicographic order. Implement: `pyt...

Coding & Algorithms
3
1
13 people solved
Jul 3, 2026
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Google
Medium
Software Engineer Locked

Solve Rooms and Top-K Streams

This question evaluates algorithmic problem-solving skills across interval scheduling/resource allocation and streaming top-k maintenance, testing com...

Coding & Algorithms
6
0
43 people solved
Jun 5, 2026
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Google
Medium
Software Engineer

Find the Largest Monotone Increasing Number

Find the Largest Monotone Increasing Number Problem Given a non-negative integer n, return the largest integer less than or equal to n whose decimal d...

Coding & Algorithms
6
1
19 people solved
Jul 4, 2026
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Google
Medium
Software Engineer

Check Whether Digits Are Monotone Increasing

Check Whether Digits Are Monotone Increasing Problem A non-negative integer has monotone increasing digits when every adjacent pair of digits is non-d...

Coding & Algorithms
4
0
19 people solved
Jul 4, 2026
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Google
Medium
Software Engineer

Group movies via graph traversal

You are given n movies labeled 0..n-1 and a list of undirected pairs (a, b) meaning movies a and b are similar. Group all movies into categories where...

Coding & Algorithms
8
0
142 people solved
Sep 6, 2025
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Google
Easy
Software Engineer Locked

Deterministic Task Execution Order

This question evaluates a candidate's ability to model task dependencies as a directed graph and produce a valid execution order, a core graph algorit...

Coding & Algorithms
2
1
11 people solved
Jun 22, 2026
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Google
Medium
Software Engineer Locked

Choose optimal guesses for green-only Wordle

This question evaluates probabilistic reasoning, expected-value optimization, information partitioning, and algorithmic efficiency in selecting guesse...

Coding & Algorithms
9
1
109 people solved
Oct 14, 2025
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Google
Medium
Software EngineerNew Grad

Return Unique Three-Sum Value Triples

Return Unique Three-Sum Value Triples Problem Implement threeSumTarget(nums, target) -> triples. Return every distinct value triple [a, b, c] for whic...

Coding & Algorithms
1
0
15 people solved
Dec 8, 2025
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Google
Medium
Software Engineer

Find fair split of a two-color necklace

Given a circular necklace represented by a string s over {'a','b'}, you may cut the necklace at most twice (yielding three contiguous pieces). Can you...

Coding & Algorithms
12
0
154 people solved
Sep 6, 2025
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Google
Medium
Software EngineerIntern Locked

Find Minimum Rooms Needed

This question evaluates understanding of interval scheduling and conflict detection in time ranges, along with algorithmic reasoning and appropriate d...

Coding & Algorithms
168
1
1403 people solved
Mar 19, 2026
Google logo
Google
Medium
Software EngineerNew Grad

Return the Lexicographically Smallest Two-Sum Index Pair

Return the Lexicographically Smallest Two-Sum Index Pair Problem Implement twoSumSmallestPair(nums, target) -> pair. Return the lexicographically smal...

Coding & Algorithms
2
0
14 people solved
Dec 8, 2025
Google logo
Google
Medium
Software EngineerNew Grad

Track the Running Median of an Integer Stream

Track the Running Median of an Integer Stream Problem Implement runningMedianTwice(values) -> mediansTwice. Process values from left to right. After e...

Coding & Algorithms
1
0
13 people solved
Dec 8, 2025
Google logo
Google
Hard
Software EngineerSenior+ Locked

Infection Spread on a Grid (Cellular Automaton)

This question tests a candidate's ability to implement and optimize a synchronous cellular automaton simulation on a 2D grid, assessing proficiency in...

Coding & Algorithms
4
0
18 people solved
Jun 14, 2026
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Google
Medium
Software Engineer

Troubleshoot CPU, latency, and DNS issues

A) A Linux server’s CPU usage suddenly spikes. What immediate checks and commands would you run (e.g., top/htop, pidstat, perf, iostat), how would you...

Coding & Algorithms
6
0
107 people solved
Sep 6, 2025
Google logo
Google
Medium
Software Engineer

Determine validity after digit-constrained deletions

Determine validity after digit-constrained deletions You're given a string S of length n consisting only of '(' , ')' , and digits '0'–'9'. For every ...

Coding & Algorithms
14
0
163 people solved
Aug 8, 2025
Google logo
Google
Medium
Software Engineer

Check if all substrings are anagrams of words

You are given a string s (letters only) and access to an English dictionary dict (a set of valid words). Return true if every contiguous substring of ...

Coding & Algorithms
60
0
565 people solved
Mar 11, 2026

Frequently Asked Questions

How difficult are Google Coding & Algorithms interviews?
Google coding and algorithms rounds are typically medium-to-hard on a LeetCode-style scale, with difficulty increasing by level and role. Phone screens usually target solid problem-solving and clean coding at a medium-to-hard level, while onsite/loop rounds expect more polished, optimized solutions and harder algorithmic thinking for senior roles. Interviewers evaluate algorithm design, correct and maintainable code, complexity trade-offs, and communication. Expect follow-ups that push for edge-case handling and performance improvements. Preparing with progressively harder problems and mock interviews helps bridge the gap to the typical onsite bar.
What is the typical Google interview process and where do Coding & Algorithms questions appear?
The process commonly starts with a recruiter screen, followed by one or two technical phone/video screens that include live coding on a shared environment, and then a virtual or onsite loop of four to six interviews that mix coding, system design (for senior candidates), and behavioral assessments. Coding and algorithms questions appear in the phone screens and in multiple onsite rounds, often as one to two algorithmic problems per technical interview. New graduate roles may include an online assessment stage. The shared-coding document or collaborative pad is a common environment for real-time problem solving.
How long should I prepare for Google Coding & Algorithms interviews?
A focused preparation timeline often ranges from six to eight weeks for candidates with solid fundamentals, and from two to four months for those rebuilding skills or targeting senior levels. Early weeks should refresh data structures, complexity analysis, and basic algorithms; middle weeks should emphasize consistent timed practice of medium to hard problems and pattern recognition; final weeks should include mock interviews, whiteboard or shared-doc practice, and review of common failure cases. Allocate regular, spaced practice and iterative feedback to close gaps, and simulate the exact environment (no IDE, shared doc) before real interviews.
What key subtopics within Coding & Algorithms should I focus on for Google interviews?
Focus on core data structures (arrays, strings, linked lists, stacks, queues, trees, graphs, heaps, and hash tables) and algorithms (sorting, searching, DFS/BFS, shortest paths, topological sorts, greedy strategies, and dynamic programming). Master complexity analysis, common patterns like two-pointers, sliding window, recursion/backtracking, and graph traversal. Also practice windowed aggregates, prefix sums, CTE-like problem decomposition in coding interviews, handling NULLs/edge cases, and thinking about performance trade-offs. Clean, testable code and the ability to explain correctness and runtime are as important as finding a working solution.
What standout tips and common pitfalls should I know when preparing for Google Coding & Algorithms interviews?
Standout tips include asking clarifying questions before coding, outlining the approach and complexity up front, writing a correct simple solution before optimizing, and walking through test cases aloud. Practice in a shared-doc or whiteboard style to mirror the interview environment and time-box your practice. Common pitfalls are not communicating thought process, ignoring constraints and edge cases, prematurely optimizing without a correct baseline, and submitting untested code. Also avoid verbose or unreadable code; prioritize clarity. Mock interviews with feedback are one of the fastest ways to fix these recurring mistakes.

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