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Coding & Algorithms Interview Questions
Practice 9403 coding, system design and machine learning questions from 546 companies, sorted by role, topic and interview round. Every question has step-by-step hints, a code runner that supports 8 languages and an AI mentor; members also get the full solution walkthrough.
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Showing 151–180 of 3276 results
- AmazonMediumSoftware EngineerDrone Circular Route — Minimum Total Travel Cost
This problem tests your ability to solve a variation of the Traveling Salesman Problem using bitmask dynamic programming to optimize route costs in a small, weighted graph.
Coding & AlgorithmsOnline AssessmentDynamic ProgrammingBitmaskingGraph Theory - AmazonMediumSoftware EngineerEscalation Stack That Resolves the Most-Reported Issue First
Design a support-escalation structure where resolving an issue always clears whichever one currently has the most open reports, breaking ties by the most recently reported occurrence. Tests combining frequency and recency so both operations run in O(1).
Coding & AlgorithmsOnsitestackhash-mapdesign - AmazonHardSoftware EngineerEvaluate IP Access Rules
This question evaluates knowledge of IPv4 addressing, CIDR subnet matching, and access-control rule resolution, assessing competency in bitwise address reasoning, prefix-length precedence, and rule tie-breaking.
Coding & AlgorithmsTechnical Screen - AmazonHardSoftware EngineerFewest Severity Inversions When Interleaving Two Patch Queues
Merge two severity-labeled patch queues into one install order that keeps each queue's internal order, and return the minimum number of severity inversions over every valid merge. Tests DP over two sequences and efficient counting with letters as priorities.
Coding & AlgorithmsOnline Assessmentdynamic-programmingstringsinversions - AmazonHardSoftware EngineerFind Longest Activatable Server Streak
This problem tests your ability to use the sliding window technique to find the longest contiguous subarray that satisfies a specific count-based constraint.
Coding & AlgorithmsOnline AssessmentSliding WindowTwo PointersArray - AmazonHardSoftware EngineerFind Two-Word Compound Words
This problem tests string manipulation, hash set lookups, and the ability to efficiently identify compound words formed by the concatenation of exactly two distinct words from a provided collection.
Coding & AlgorithmsTechnical ScreenStringsHash SetAlgorithms - AmazonHardSoftware EngineerFind a Maximum-Sum Window in a Sparse Array
This problem tests the ability to optimize sliding window calculations for extremely large arrays by leveraging compressed data structures (run-length encoding) rather than materializing the full array.
Coding & AlgorithmsOnline AssessmentSliding WindowArraysOptimization - AmazonHardSoftware EngineerFind a Valid Course Order
This problem tests your ability to detect cycles in a directed graph and perform a topological sort to resolve dependencies.
Coding & AlgorithmsOnsiteGraphsTopological SortKahn's Algorithm - AmazonMediumSoftware EngineerFind a valid dependency order
This question evaluates understanding of directed graphs, dependency resolution and cycle detection, and the ability to reason about valid ordering constraints within a graph representation.
Coding & AlgorithmsOnline Assessment - AmazonEasySoftware EngineerFind all cells reachable by downhill flow
This question evaluates graph traversal and reachability reasoning on a 2D elevation grid, testing algorithmic problem-solving, complexity analysis, and handling of monotonic flow constraints.
Coding & AlgorithmsTechnical Screen - AmazonMediumSoftware EngineerFind concatenated words in list
This question evaluates proficiency in string manipulation, efficient lookup structures (e.g., hashing/trie) and dynamic programming or recursion for word segmentation, testing algorithmic efficiency and data-structure selection within the Coding & Algorithms domain.
Coding & AlgorithmsTechnical Screen - AmazonMediumSoftware EngineerFind first unique character
Find first unique character evaluates algorithm design, data structures, correctness, complexity, edge cases, and implementation details in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Coding & AlgorithmsTechnical Screen - AmazonMediumSoftware EngineerFind longest common contiguous subarray
This question evaluates a candidate's proficiency in array and substring algorithm design, including concepts such as dynamic programming, hashing, and efficient search techniques.
Coding & AlgorithmsOnsite - AmazonMediumSoftware EngineerFind longest segment with dominant ends
This question evaluates algorithmic problem-solving with arrays and complexity-aware design, testing skills in efficient subarray identification, boundary reasoning, and performance analysis within the Coding & Algorithms domain.
Coding & AlgorithmsOnline Assessment - AmazonMediumSoftware EngineerFind longest segment with endpoints > interior
This question evaluates algorithmic design and array-processing skills, specifically reasoning about subarray endpoint vs interior relationships, range comparisons, and designing solutions with subquadratic time and space complexity.
Coding & AlgorithmsOnline Assessment - AmazonMediumSoftware EngineerFind max equal-frequency block count for each prefix
This problem tests your ability to efficiently manage character frequency tracking while processing string prefixes, using hash maps or frequency arrays to validate partitioning conditions.
Coding & AlgorithmsTechnical ScreenStringsDynamic ProgrammingHash Map - AmazonMediumSoftware EngineerFind minimum days to deliver all orders
This question evaluates algorithm design and combinatorial optimization skills, focusing on scheduling and load-balancing under per-center capacity constraints and frequency-based counting.
Coding & AlgorithmsOnline Assessment - AmazonMediumSoftware EngineerFind minimum time for irrecoverable password
This question evaluates string-processing skills, combinatorial counting of substrings, simulation of time-based state changes, and algorithmic complexity analysis.
Coding & AlgorithmsOnline Assessment - AmazonMediumSoftware EngineerFind minimum total range-increment to sort
This problem tests your ability to determine the minimum total operations required to make an array non-decreasing by incrementing contiguous subarrays, requiring insights into difference arrays or monotonic properties.
Coding & AlgorithmsOnline AssessmentGreedyArraysDifference Array - AmazonMediumSoftware EngineerFind returning users from access logs
This question evaluates skills in time-series data processing, timestamp parsing and time-zone normalization, scalable stream or batch handling for logs that exceed memory, algorithmic complexity analysis, and test-case design for edge conditions such as midnight boundaries and duplicate events.
Coding & AlgorithmsOnsite - AmazonMediumApplied ScientistFind shortest path in a grid with obstacles
This question evaluates understanding of pathfinding in grid-based environments, graph traversal concepts, and algorithmic complexity when navigating obstacles and boundary constraints in an unweighted 2D search space.
Coding & AlgorithmsOnsite - AmazonMediumSoftware EngineerFind shortest subarray to restore order
This question evaluates array manipulation and algorithmic problem-solving skills, focusing on understanding how local subarray sorting affects global order, edge-case reasoning (already-sorted arrays, duplicates, strictly decreasing sequences), and complexity analysis within the Coding & Algorithms domain.
Coding & AlgorithmsTechnical Screen - AmazonMediumApplied ScientistFind shortest transformation steps in a word graph
This question evaluates a candidate's ability to model string transformations as a graph, apply graph traversal and shortest-path reasoning, and manage efficient string-based search and data-structure choices within the Coding & Algorithms domain.
Coding & AlgorithmsTechnical Screen - AmazonHardSoftware EngineerFind the Closest Version by Date
This problem tests your ability to efficiently search through chronologically ordered records and handle binary search logic with custom comparison rules.
Coding & AlgorithmsOnsiteBinary SearchArraysAlgorithms - AmazonEasySoftware EngineerFind the Earliest Pair with a Target Sum
Tests array traversal and hash table lookups to find a two-sum pair that minimizes the second index, running in linear time and space.
Coding & AlgorithmsTechnical Screenarrayhash-tabletwo-sum - AmazonMediumSoftware EngineerFind the K Most Frequent Values
Find any valid set of the k most frequent distinct integers, handling boundary ties with frequency counting, bounded heaps, or frequency buckets.
Coding & AlgorithmsOnline Assessment - AmazonMediumSoftware EngineerFind the K-th Smallest Value in Two Sorted Arrays
Given two nondecreasing integer arrays and a one-based integer k, return the k-th smallest value in their combined multiset. Work through the function contract, boundary cases, correctness argument, and time and space complexity expected in a production-quality solution.
Coding & AlgorithmsTechnical Screen - AmazonMediumSoftware EngineerFind the Kth Smallest Value in a Binary Search Tree
Deserialize a level-order serialized binary search tree and find its kth smallest element using an efficient in-order traversal.
Coding & AlgorithmsOnsitebinary-search-treetree-traversalstack - AmazonHardSoftware EngineerFind the Largest Rating Threshold Supported by K Instances
Find the largest k for which at least k instance ratings are at least k, handling threshold equality and the zero-answer case.
Coding & AlgorithmsOnline Assessment - AmazonEasySoftware EngineerFind the Lowest Common Ancestor in a Binary Tree
This problem tests tree traversal techniques and recursive logic to identify the deepest node that is an ancestor to two specified nodes within a binary tree.
Coding & AlgorithmsTechnical ScreenBinary TreeRecursionDFS
Amazon