Coding & Algorithms Interview Questions

Practice 3,429 real Coding & Algorithms interview questions for 2026. Covers companies like Meta, Amazon, Google, Uber, and Microsoft. Real questions from actual interviews with detailed solutions — ideal for focused interview preparation. Coding & Algorithms interview questions are the single most common technical gate for software engineering roles and are used to evaluate problem framing, algorithm selection, complexity trade-offs, correctness, edge-case reasoning, and clear communication under time pressure. Expect this category to appear in early technical screens and repeatedly across onsite loops at companies that weight it heavily (notably Meta, Google, and Amazon). Interviews will test arrays and strings, trees and graphs, dynamic programming, hashing and two‑pointer techniques, and the candidate’s ability to test and optimize code in a shared editor. Prepare with timed mock interviews, practice in the same editor you’ll use live, and build a progressive schedule that moves from fundamentals to medium/hard problems; typical candidates invest several weeks to a few months of focused practice depending on seniority and target company.

3.4k Questions 368 Companies08.11.2026
Showing 20 results
Role
Pinduoduo logo
Pinduoduo
Medium
Software Engineer

Implement a Followable Microblog Timeline

Implement a Followable Microblog Timeline Design an in-memory microblog service with these operations: `text post(user_id, tweet_id) follow(follower_i...

Coding & Algorithms
0
0
14 people solved
Jul 26, 2026
Uber logo
Uber
Medium
Software EngineerIntern

Kth Employee Reached in an Ordered Hierarchy

Kth Employee Reached in an Ordered Hierarchy Implement kth_recipients(boss, queries). Employees are numbered 0 through n - 1. boss[0] == -1; for every...

Coding & Algorithms
11
0
155 people solved
Jul 3, 2026
Amazon logo
Amazon
Medium
Software Engineer

Track Missing Package IDs from Out-of-Order Receipts

Packages have nonnegative integer IDs starting at 0, but they may be received out of order. Support two operations: - receive(id) records that package...

Coding & Algorithms
0
0
8 people solved
Aug 1, 2026
Bytedance logo
Bytedance
Easy
Software Engineer

Merge Overlapping Intervals

Merge Overlapping Intervals Implement merge_intervals(intervals) for a list of closed integer intervals. Each interval is [start, end] with start <= e...

Coding & Algorithms
1
0
21 people solved
Jul 22, 2026
Bytedance logo
Bytedance
Medium
Data Scientist

Determine Whether an Integer Is a Palindrome

Determine Whether an Integer Is a Palindrome Implement is_palindrome_number(value). Return true when the base-10 digits of a non-negative integer read...

Coding & Algorithms
1
0
7 people solved
Aug 3, 2026
Netflix logo
Netflix
Medium
Software Engineer

Find the Longest Substring Without Repeated Characters

Find the Longest Substring Without Repeated Characters Problem Implement longestUniqueSubstringLength(text) -> length. Return the length of the longes...

Coding & Algorithms
1
0
8 people solved
Jul 31, 2026
Pinterest logo
Pinterest
Medium
Software Engineer

Select the Nearest Eligible Elevator

Select the Nearest Eligible Elevator You are given a list of elevators. Each elevator has a current integer floor and a state: "up", "down", or "idle"...

Coding & Algorithms
14
0
103 people solved
May 12, 2026
Ai2 logo
Ai2
Medium
Software EngineerSenior+

Maintain an Out-of-Order Step Progress Tree

Maintain an Out-of-Order Step Progress Tree Each progress event contains: `text timestamp: integer step_id: integer parent_step_id: integer or null ru...

Coding & Algorithms
1
0
17 people solved
Jul 20, 2026
Capital One logo
Capital One
Medium
Software Engineer

Arrange Match Results in Repeating Win-Draw-Loss Order

Arrange Match Results in Repeating Win-Draw-Loss Order You are given a string containing only W, D, and L. Rearrange all characters into rounds. In ea...

Coding & Algorithms
4
0
41 people solved
Jul 21, 2026
Point72 logo
Point72
Hard
Software Engineer

Maximize Fixed Positions After Deletions

Given an integer array a, delete zero or more elements while preserving the relative order of the elements that remain. Let the resulting array be b, ...

Coding & Algorithms
0
0
7 people solved
Aug 1, 2026
Point72 logo
Point72
Hard
Software Engineer

Simulate a Deterministic Finite Automaton

Implement a deterministic finite automaton simulator for the alphabet {a, b}. The automaton has states numbered from 0 through stateCount - 1. The tra...

Coding & Algorithms
0
0
7 people solved
Aug 1, 2026
Jump Trading logo
Jump Trading
Medium
Data Scientist

Maintain a Fixed-Window Rolling Mean in Constant Time

Maintain a Fixed-Window Rolling Mean in Constant Time Implement rolling_means(values, window) for signed integer values, returning a double-precision ...

Coding & Algorithms
0
0
4 people solved
Aug 8, 2026
Anthropic logo
Anthropic
Medium
Software Engineer

Banking System Simulation

Banking System Simulation You are building an in-memory banking system that is driven by a time-ordered stream of operations. Implement the system so ...

Coding & Algorithms
6
0
57 people solved
Jun 23, 2026
Amazon logo
Amazon
Medium
Software Engineer

Resolve Package Dependencies with Cycle Detection

Implement buildOrder(dependencies, target), which returns the packages needed to build and install target in a valid dependency-first order. dependenc...

Coding & Algorithms
0
0
8 people solved
Jul 29, 2026
Google logo
Google
Medium
Software Engineer Locked

Sliding Window Average After Dropping the Largest Values

Compute one average per fixed-size sliding window after removing exactly the largest k values, counting duplicates separately. Support negative number...

Coding & Algorithms
19
1
145 people solved
May 23, 2026
Pinterest logo
Pinterest
Medium
Software Engineer

List Unallocated Experiment Buckets

List Unallocated Experiment Buckets Problem An experiment system divides traffic into numbered buckets. Implement findUnallocatedBuckets(bucketCount, ...

Coding & Algorithms
1
0
11 people solved
Jul 23, 2026
Amazon logo
Amazon
Hard
Software Engineer AI

Circular Drone Hub Delivery Route

A drone delivery network is laid out as a ring of n hubs, numbered 0, 1, ..., n - 1. Each hub is connected by a direct air corridor to its two neighbo...

Coding & Algorithms
5
0
60 people solved
Jun 28, 2026
Amazon logo
Amazon
Easy
Software EngineerIntern

Determine Whether One Person Can Attend Every Meeting

Determine Whether One Person Can Attend Every Meeting Problem Implement canAttendAllMeetings(intervals) -> canAttend. Each meeting is a half-open inte...

Coding & Algorithms
0
0
6 people solved
Aug 1, 2026
Netflix logo
Netflix
Medium
Software Engineer

Find the Longest Run of One Character

Find the Longest Run of One Character Problem Implement longestIdenticalRun(text) -> length. Return the maximum number of consecutive positions contai...

Coding & Algorithms
0
0
6 people solved
Jul 31, 2026
Walmart Labs logo
Walmart Labs
Hard
Software Engineer

Implement a Range Module with Add, Query, and Remove

Process Range Tracking Operations Implement processRanges(operations) -> queryResults. The tracker is initially empty. Process every operation from le...

Coding & Algorithms
1
0
16 people solved
Jul 16, 2026

Frequently Asked Questions

How difficult are Coding & Algorithms interview questions?
Difficulty spans a wide range: from quick easy warm-ups to multi-stage hard problems that require advanced data structures or algorithmic proofs. Most companies place a majority of live coding rounds at the medium level, with occasional hard questions used to distinguish senior candidates. Interviewers evaluate problem framing, algorithm choice, time/space complexity, clean implementation, and thoughtful testing under time pressure. Expect more conceptual depth at Google, more consistent medium-to-hard screens at Meta, and Amazon to mix coding with leadership signals. Leveling depends on role and seniority: entry-level focuses on fundamentals; senior roles emphasize design, optimizations, and tradeoffs.
Where does Coding & Algorithms appear in a typical interview loop, and which companies weight it most heavily?
Coding & Algorithms is usually the first technical hurdle: it appears in phone/online screens, followed by one or more onsite or virtual coding rounds during the loop. Typical sequences are a technical screen, two to three in-loop coding sessions, then system design or behavioral rounds. Companies that weight this category heavily include Google, Meta, and Amazon, where coding performance often determines whether you progress. Candidates commonly concentrate practice for weeks or months beforehand; most targeting large tech firms prepare intensively for 6–12 weeks, while some spend 3–6 months for deeper mastery or level changes.
How long should I prepare and how should I structure that preparation?
Plan focused, progressive practice over a realistic timeline. A practical structure is an 8–12 week block: weeks 1–2 solidify fundamentals and language fluency; weeks 3–6 target core patterns (arrays, trees, graphs, DP) with timed problem sessions and pattern tagging; weeks 7–9 emphasize mock interviews, end-to-end problem solving, and optimization tradeoffs; final weeks simulate real loops with full-length sessions and targeted weak-point drills. Candidates with less experience may extend to 12–16 weeks. Regularly review mistakes, practice communicating solutions aloud, and include at least one weekly mock interview with peer or coach feedback.
What key subtopics and patterns should I master for Coding & Algorithms interviews?
Master a consistent set of patterns and their variations: arrays and strings (two pointers, sliding window), hash maps and frequency counts, sorting and binary search, recursion and backtracking, dynamic programming, trees and traversals, graphs (BFS/DFS, shortest paths, union-find), heaps and priority queues, and greedy algorithms. Also practice complexity analysis, space-time tradeoffs, and writing bug-resistant code with tests. For higher levels, focus on amortized analysis, advanced graph algorithms, segment trees or Fenwick trees, and system-aware optimizations. Interviewers value reusable problem templates and the ability to generalize patterns to new prompts.
What are standout tips and common pitfalls to avoid in Coding & Algorithms interviews?
Start by clarifying requirements and constraints, then outline your approach before coding. Write a correct, readable baseline solution first, then iterate to improve complexity while narrating tradeoffs. Test with simple and edge cases, and handle nulls, off-by-one, and empty inputs explicitly. Communicate continuously; silence looks like confusion. Avoid premature optimization, overcomplicating solutions, or ignoring interviewer hints. Time management matters: if stuck, discuss alternate approaches and code a partial solution. Finally, practice mock interviews to reduce anxiety and build the habit of clear, structured explanations under pressure.

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