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
Plaid logo
Plaid
Medium
Software Engineer

Calculate Ordered Job Makespan Across Parallel Workers

Calculate Ordered Job Makespan Across Parallel Workers A single stage has jobs with different durations and a fixed number of identical workers. Jobs ...

Coding & Algorithms
9
1
66 people solved
Jul 13, 2026
Google logo
Google
Medium
Software EngineerNew Grad Locked

Search a Pattern Across the Leaf Text of a Binary Tree

Search for a pattern across the left-to-right concatenation of binary-tree leaf strings, including matches that cross leaf boundaries. This algorithm ...

Coding & Algorithms
19
1
159 people solved
Jun 17, 2026
Google logo
Google
Medium
Software Engineer

Minimum Cars for Rental Requests

Minimum Cars for Rental Requests You receive rental requests, each with a unique request identifier, pickup time, and return time. Every request must ...

Coding & Algorithms
1
0
11 people solved
Aug 1, 2026
Amazon logo
Amazon
Easy
Software EngineerIntern

Find the Most Frequently Used Meeting Room

Find the Most Frequently Used Meeting Room Problem Implement mostBookedRoom(roomCount, meetings) -> roomId. Rooms are numbered 0 through roomCount - 1...

Coding & Algorithms
1
0
11 people solved
Aug 1, 2026
Amazon logo
Amazon
Easy
Software EngineerIntern

Compute the Minimum Number of Meeting Rooms

Compute the Minimum Number of Meeting Rooms Problem Implement minimumMeetingRooms(intervals) -> roomCount. Each meeting is a half-open interval [start...

Coding & Algorithms
0
0
11 people solved
Aug 1, 2026
Amazon logo
Amazon
Easy
Software EngineerIntern

Find the Lowest Common Ancestor in a Binary Tree

Find the Lowest Common Ancestor in a Binary Tree Problem Implement lowestCommonAncestor(left, right, root, first, second) -> nodeId. The binary tree h...

Coding & Algorithms
1
0
11 people solved
Aug 1, 2026
Bytedance logo
Bytedance
Medium
Software Engineer

Merge Overlapping Closed Intervals

Implement merge_intervals(intervals) for closed intervals. Return disjoint closed intervals that cover exactly the same points, sorted by start. Inter...

Coding & Algorithms
0
0
6 people solved
Aug 9, 2026
Netflix logo
Netflix
Medium
Software Engineer

Report Tree Levels and Balanced Subtrees

Implement describe_balanced_nodes(values) for a binary tree represented as a zero-based heap array. For an existing node at index i, its children are ...

Coding & Algorithms
0
0
5 people solved
Aug 11, 2026
Plaid logo
Plaid
Medium
Software Engineer

Count Completed Jobs in a Serial Multi-Worker Pipeline

Count Completed Jobs in a Serial Multi-Worker Pipeline An automation pipeline contains stages that execute in order. Each stage is represented as [num...

Coding & Algorithms
6
0
55 people solved
Jul 13, 2026
Uber logo
Uber
Medium
Software EngineerIntern

Minimum Delivery Cost Between Cities

Minimum Delivery Cost Between Cities Implement minimum_delivery_costs(delivery_charges, queries). There are n cities indexed from 0 to n - 1, and city...

Coding & Algorithms
15
1
124 people solved
Jul 3, 2026
Netflix logo
Netflix
Medium
Software Engineer

Count Pairs of Strings with Disjoint Character Sets

Count Pairs of Strings with Disjoint Character Sets Problem Implement countDisjointStringPairs(words) -> count. Count unordered index pairs (i, j) wit...

Coding & Algorithms
0
0
11 people solved
Jul 31, 2026
Bnsf logo
Bnsf
Hard
Software EngineerSenior+

Maximize Valid Trains from Shared Equipment

You have a pool of locomotives and railcars. Partition any subset of them into valid trains while using each locomotive and railcar at most once. A va...

Coding & Algorithms
2
0
18 people solved
Jul 23, 2026
Figma logo
Figma
Medium
Software Engineer

Validate a Balanced INDENT and DEDENT Token Stream

Validate a Balanced INDENT and DEDENT Token Stream Problem A tokenizer has already converted a document into a sequence of tokens. Two token values ha...

Coding & Algorithms
1
0
19 people solved
Jul 21, 2026
Snowflake logo
Snowflake
Medium
Software Engineer

Traverse All Reachable Pages With Parallel BFS

Problem A collection of web pages is modeled as a directed graph. graph[page] lists the pages linked from page in a stable order. Implement reachable_...

Coding & Algorithms
5
0
38 people solved
Jul 11, 2026
Salesforce logo
Salesforce
Medium
Software Engineer

Delete One Character Type to Minimize Unique Segments

Problem Implement min_unique_segments_after_deletion(s) for a nonempty lowercase English string. Choose exactly one character value that appears in s ...

Coding & Algorithms
2
0
35 people solved
Jul 13, 2026
Salesforce logo
Salesforce
Medium
Software Engineer

Maximal Square and Longest Increasing Subsequence

Problem Implement analyze(matrix, nums) and return [max_square_area, lis_length]. Part A: Maximal Square matrix is a rectangular grid containing only ...

Coding & Algorithms
2
0
39 people solved
Jul 9, 2026
Two Sigma logo
Two Sigma
Medium
Software EngineerNew Grad

Allocate IPO Shares and Split a Weighted Tree

Two Allocation and Tree Problems Implement both independent parts. Part A - IPO Share Allocation Each bid is [user_id, requested_shares, price, timest...

Coding & Algorithms
3
0
49 people solved
Jun 28, 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
Visa logo
Visa
Medium
Software EngineerSenior+

Count Perfect Digit-Frequency Substrings

Count Perfect Digit-Frequency Substrings Problem Implement countPerfectSubstrings(s, k). The string s contains only decimal digits. A nonempty substri...

Coding & Algorithms
0
0
8 people solved
Aug 3, 2026
Anthropic logo
Anthropic
Hard
Software Engineer

Build a Progressive Banking Ledger

Build a Progressive Banking Ledger The source reports the four feature stages but not exact ledger semantics. The APIs, event priorities, cashback tim...

Coding & Algorithms
2
0
43 people solved
Jul 8, 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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