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
Google logo
Google
Medium
Data ScientistSenior+

Implement Fibonacci with efficiency constraints

Write a function fib(n) that returns the nth Fibonacci number (0-indexed: fib(0)=0, fib(1)=1). Requirements: - Handle n up to at least 10^6. - Discuss...

Coding & Algorithms
6
0
56 people solved
Nov 24, 2025
Google logo
Google
Hard
Software Engineer

Count same-color squares in a character grid

You are given a 2D grid (matrix) of characters. Each character represents a color: cells with the same character are considered the same color. Formal...

Coding & Algorithms
13
1
157 people solved
Nov 22, 2025
Google logo
Google
Medium
Software Engineer

Compute servers needed for daily recurring jobs

You operate a cluster of identical servers that run recurring daily jobs. For a single day, you are given a list of job execution intervals. Each inte...

Coding & Algorithms
15
0
144 people solved
Nov 5, 2025
Google logo
Google
Medium
Software Engineer

Minimize calls to find all bad test pairs

You have \(n\) atomic tests \(t_1, t_2, \dots, t_n\). You are given access to a black-box function: `python bool runTest(set<Test> S) ` which behaves ...

Coding & Algorithms
13
0
140 people solved
Nov 5, 2025
Google logo
Google
Medium
Software Engineer

Find shared objects across two log files

You are given two large log files representing activity on two different days. Each line of each log has three fields: - timestamp: a time value (you ...

Coding & Algorithms
6
0
79 people solved
Nov 5, 2025
Google logo
Google
Easy
Software Engineer

Find right-side view of binary tree

You are given the root of a binary tree. From the right side of the tree, at each depth you can see exactly one node: the rightmost node at that depth...

Coding & Algorithms
6
0
63 people solved
Nov 1, 2025
Google logo
Google
Easy
Data Scientist

Match payments to invoices by memo or amount

Scenario You are building a small reconciliation tool that matches payments to invoices. Data structures Assume you are given: - invoices: a list of i...

Coding & Algorithms
8
0
57 people solved
Oct 25, 2025
Google logo
Google
Medium
Data Scientist

Match payments to invoices by memo or amount

You are building a small payment-to-invoice matching utility. Data You are given: - invoices: a list of invoice records with: - invoice_id (string) ...

Coding & Algorithms
5
0
51 people solved
Oct 19, 2025
Google logo
Google
Easy
Software Engineer

Compute max coins with 3-step token moves

You are given a one-dimensional board with n positions represented by a string s of length n: - . = empty cell - T = token - C = coin You may move tok...

Coding & Algorithms
22
0
151 people solved
Oct 16, 2025
Google logo
Google
Medium
Data Scientist

Implement percentage RMSE and bootstrap its CI

Given a CSV with columns [country, actual_revenue, predicted_revenue], define percentage RMSE as pRMSE = sqrt(mean_i((pred_i/actual_i − 1)^2)). a) Imp...

Coding & Algorithms
6
0
49 people solved
Oct 13, 2025
Google logo
Google
Medium
Data Scientist

Implement longest subarray summing to k

Given an integer array nums (length ≤ 200,000; values may be negative) and integer k, return the maximum length and the [l, r] indices of a contiguous...

Coding & Algorithms
8
0
68 people solved
Oct 13, 2025
Google logo
Google
Medium
Software Engineer

Count user sessions from logs

Given a large log file where each line is "timestamp,user,action", compute the number of sessions per user. Assume a session ends if the gap between c...

Coding & Algorithms
11
0
82 people solved
Sep 6, 2025
Google logo
Google
Medium
Software Engineer

Optimize 0/1 to bounded knapsack DP

Solve the 0/1 knapsack problem: given arrays weight[i], value[i] for i=0..n-1 and capacity W, return the maximum value and reconstruct one optimal set...

Coding & Algorithms
5
0
89 people solved
Sep 6, 2025
Google logo
Google
Medium
Software Engineer

Find minimum covering substring

Given two strings s and t, return the shortest contiguous substring of s that contains every character of t with at least the same multiplicities. If ...

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

Find horizontal cut balancing square areas

Given a 2D table with top-left origin (0, 0), you are provided a finite set of n non-overlapping, axis-aligned square cakes. Each square i has real-va...

Coding & Algorithms
3
0
43 people solved
Sep 6, 2025
Google logo
Google
Medium
Software Engineer

Maximize coins collected by 3-step pieces

You are given a 1D board of length N. Each cell is in one of three states: - Empty - Piece (a movable token) - Coin (collectible) In one move, you may...

Coding & Algorithms
4
0
71 people solved
Sep 5, 2025
Google logo
Google
Medium
Data Scientist

Simulate Coin Flips to Determine Fairness via Empirical Distribution

Scenario You must test whether a coin is fair by simulation. Question Write code that repeatedly simulates n coin flips, records the number of heads, ...

Coding & Algorithms
6
0
60 people solved
Aug 4, 2025
Google logo
Google
Medium
Software Engineer

Implement zigzag level-order traversal

Given the root of a binary tree, return the node values in zigzag level order: visit nodes level by level, reading the first level from left to right,...

Coding & Algorithms
7
1
61 people solved
Aug 1, 2025
Google logo
Google
Medium
Software Engineer

Parse strings and find meeting slots

Question Given a text file where each line contains raw information, extract the user identifier and the numeric quantity on that line and store the r...

Coding & Algorithms
31
0
61 people solved
Jul 29, 2025
Google logo
Google
Medium
Data Scientist

Normalize Columns in Binomial Matrix Efficiently

Scenario Write code that creates a 100×100 matrix of Binomial(1, 0. 5) samples and normalizes each column so it sums to 1. Question Provide an efficie...

Coding & Algorithms
14
0
31 people solved
Jul 12, 2025

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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