Coding & Algorithms Interview Questions

Practice 3,469 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.

3.5k Questions 368 Companies08.11.2026
Showing 20 results
Role
Lyft logo
Lyft
Medium
Software Engineer Locked

Assign Minimum Workers to Jobs

This question evaluates a candidate's understanding of interval scheduling, resource allocation, and time arithmetic for converting HHMM timestamps to...

Coding & Algorithms
1
0
36 people solved
Apr 3, 2026
Toma logo
Toma
Medium
Software Engineer Locked

Implement AudioStream Mixer

This question evaluates skill in designing stateful data structures, time-indexed array manipulation, and per-track mixing semantics including overwri...

Coding & Algorithms
3
0
26 people solved
Apr 3, 2026
Snowflake logo
Snowflake
Medium
Software Engineer

Compute task order and layered execution

You have N tasks labeled 0..N-1 and prerequisite pairs (a, b) meaning task a must complete before task b can start. Return any valid execution order o...

Coding & Algorithms
8
0
126 people solved
Sep 6, 2025
Meta logo
Meta
Medium
Software Engineer AI

Extend a Maze Solver

You are given an existing codebase for a maze game and solver. The maze is represented as a 2D grid containing: - S: start cell - T: target cell - .: ...

Coding & Algorithms
4
0
40 people solved
Jan 6, 2026
Aurora logo
Aurora
Medium
Software Engineer Locked

Find viewing direction that sees most points

This question evaluates computational geometry skills, angular normalization and counting within a sector, and the ability to design algorithms that s...

Coding & Algorithms
9
0
112 people solved
Jan 6, 2026
Waymo logo
Waymo
Medium
Software Engineer Locked

Validate a Parent-Child Forest

This question evaluates understanding of graph theory concepts—specifically rooted trees, parent-child relationships, cycle detection, and node in-deg...

Coding & Algorithms
1
0
11 people solved
May 27, 2026
Shopify logo
Shopify
Medium
Software Engineer AI

Implement a Constant-Time LRU Cache

Implement a Constant-Time LRU Cache Implement a fixed-capacity least-recently-used cache. The captured source identifies an LRU cache coding problem b...

Coding & Algorithms
3
0
21 people solved
Apr 28, 2026
Google logo
Google
Medium
Software Engineer

Find the Longest Consecutive Path in a Binary Tree

Given a binary tree, return the length of the longest downward path where each child value is exactly one greater than its parent value. Nodes have va...

Coding & Algorithms
0
0
6 people solved
Apr 28, 2026
Amazon logo
Amazon
Medium
Software Engineer

Find Valid IP Addresses in Files

You are given an absolute or relative path to a directory on the local file system. Write a program that recursively traverses every subdirectory unde...

Coding & Algorithms
37
0
292 people solved
Apr 28, 2026
Two Sigma logo
Two Sigma
Hard
Data ScientistIntern Locked

Merge two sorted linked lists

This question evaluates proficiency with linked list data structures, pointer manipulation, in-place merging concepts, and algorithmic efficiency with...

Coding & Algorithms
4
0
51 people solved
Apr 2, 2026
Google logo
Google
Medium
Software Engineer

Determine if a 14-tile hand is winning

You are given an integer array tiles of length 14 representing a Mahjong-like hand. Each integer is a tile value from 1 to 9 (single suit). You may re...

Coding & Algorithms
20
0
203 people solved
Mar 9, 2026
Amazon logo
Amazon
Hard
Machine Learning EngineerNew Grad

Implement Optimal Bucket Batching

You are given an array lengths of K document lengths and an integer G representing the number of available GPUs. A batch is assigned to one GPU, and e...

Coding & Algorithms
2
0
34 people solved
Apr 27, 2026
Apple logo
Apple
Medium
Software Engineer

Vertical Order Traversal of a Binary Tree

Vertical Order Traversal of a Binary Tree You are given the root of a binary tree. Return the vertical order traversal of its nodes' values — that is,...

Coding & Algorithms
1
0
15 people solved
Jun 30, 2026
Apple logo
Apple
Medium
Software Engineer

Convert a Roman Numeral to an Integer

Convert a Roman Numeral to an Integer Roman numerals are written with seven symbols, each with a fixed integer value: | Symbol | Value | |--------|---...

Coding & Algorithms
0
0
9 people solved
Jun 30, 2026
Nuro logo
Nuro
Medium
Software Engineer Locked

Find Intersections Between Two Interval Lists

Find every non-empty intersection between two sorted lists of disjoint closed intervals. Preserve ascending order and correctly include intersections ...

Coding & Algorithms
1
0
10 people solved
May 26, 2026
Lead logo
Lead
Medium
Software Engineer Locked

Solve friend recommendations and time-versioned maps

This question evaluates the candidate's ability to design and implement specialized data structures for graph-based friend recommendation logic and ti...

Coding & Algorithms
0
0
6 people solved
May 26, 2026
Rippling logo
Rippling
Hard
Software Engineer

Compute org height and minimal CEO promotions

You are given an organization chart with n employees labeled 1..n. Employee 1 is the CEO (root). The reporting relationships are given as two integer ...

Coding & Algorithms
33
0
499 people solved
Feb 12, 2026
Google logo
Google
Medium
Software EngineerNew Grad

Count Good Numbers up to a Limit

Count Good Numbers up to a Limit A positive integer is good when all of the following hold: 1. Its decimal representation contains no digit 0. 2. No d...

Coding & Algorithms
1
0
10 people solved
Apr 26, 2026
Google logo
Google
Medium
Software EngineerNew Grad

Find the Longest Momentum-Aware Water Path

Find the Longest Momentum-Aware Water Path Given an m × n integer height grid, find the maximum number of cells in a valid path. A path may start at a...

Coding & Algorithms
1
0
10 people solved
Apr 26, 2026
OpenAI logo
OpenAI
Medium
Machine Learning Engineer

Design a Resumable Iterator with Checkpoint and Restore

Design a resumable iterator: an iterator that can serialize its current position into a compact, opaque checkpoint and later be reconstructed from tha...

Coding & Algorithms
2
0
17 people solved
Oct 18, 2025

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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