practice a little every day, paws crossed ♡
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.
- 9403
- Questions
- 546
- Companies
- 11
- Topics
- 8
- Languages
Showing 1651–1680 of 1706 results
- WhatnotMediumSoftware EngineerBuild a Tic-Tac-Toe App
This question evaluates proficiency in interactive UI development and stateful game logic, including turn management, board state representation, win/draw detection, input validation, and reset flow.
Coding & AlgorithmsTechnical Screen - WhatnotEasySoftware EngineerCheck Whether a String Can Become a Palindrome by Deleting at Most One Character
A string coding problem that asks whether a lowercase string can be turned into a palindrome by deleting at most one character, returning a boolean. It tests careful handling of mismatched characters, strings that are already palindromes, and an efficient solution for strings of up to 100,000 characters.
Coding & AlgorithmsTechnical Screen - WhatnotMediumSoftware EngineerContent Safety Filter
Tests string tokenization, interval tracking, and Trie-based multi-word pattern matching to redact prohibited phrases from live-stream messages.
Coding & AlgorithmsTechnical ScreenStringTrieHash Table - WhatnotMediumSoftware EngineerDot Product of Two Vectors (Dense, then Sparse)
Tests data structure design and algorithmic optimization for sparse vector operations, transitioning from standard array traversal to pointer-based or hash-based solutions that scale with non-zero elements.
Coding & AlgorithmsTechnical Screenarrayhash-tabletwo-pointers - WhatnotMediumSoftware EngineerKnight Dialer: Count Dialable Digit Sequences
Calculate the number of distinct n-digit phone numbers reachable by standard chess knight moves on a numeric keypad, modulo 10^9 + 7.
Coding & AlgorithmsTechnical Screendynamic-programminggraphcombinatorics - WhatnotHardSoftware EngineerMerge Two Sorted Arrays
Implement a linear-time merge of two sorted arrays into a new sorted array using two pointers, preserving duplicates without modifying the input arrays.
Coding & AlgorithmsTechnical Screenarraystwo-pointerssorting - WhatnotHardSoftware EngineerRemove All Adjacent Duplicate Pairs
Implement an algorithm to repeatedly eliminate adjacent identical character pairs from a string until no adjacent duplicates remain, handling Unicode inputs in linear time.
Coding & AlgorithmsTechnical Screenstackstringsunicode - WhatnotEasySoftware EngineerRepeatedly Delete Adjacent Duplicate Pairs or Whole Runs of Equal Characters
A string coding problem with two modes: repeatedly delete pairs of equal adjacent characters, or, as the follow-up, delete whole runs of equal adjacent characters, always the leftmost run first, and return what remains. It tests simulating cascading deletions efficiently and handling runs that merge after a deletion.
Coding & AlgorithmsTechnical Screen - WhatnotEasySoftware EngineerSolve Adjacent-Deletion and Sorted-Square Problems
This question evaluates skills in string manipulation and pattern-removal algorithms for adjacent duplicates and k-sized group deletions, as well as array processing and merging techniques for producing sorted squares; it tests understanding of relevant data-structure concepts and merging/two-pointer strategies within the Coding & Algorithms domain. It is commonly asked to assess algorithmic efficiency, correctness under large input constraints and tricky edge cases (such as cascading deletions and negative values), and is primarily a practical implementation task that emphasizes complexity analysis over purely theoretical reasoning.
Coding & AlgorithmsTechnical Screen - XPengMediumData EngineerBuild a Least-Recently-Used Store
This question evaluates understanding of caching and eviction policies and practical proficiency with data structures such as hash tables and ordered collections for tracking and updating recency.
Coding & AlgorithmsTechnical Screen - XPengMediumSoftware EngineerImplement Stable Softmax
This question tests the ability to implement a numerically stable softmax function by handling potential floating-point overflows or underflows common in high-dimensional vector exponentiation.
Coding & AlgorithmsTechnical ScreenNumerical MethodsSoftmaxFloating-Point Arithmetic - XiaohongshuMediumSoftware EngineerFind the Unique Element in Pairs
This problem tests your ability to use binary search on a sorted array to find a unique element where all other elements appear in identical pairs.
Coding & AlgorithmsTechnical ScreenBinary SearchArraysDivide and Conquer - XiaohongshuMediumSoftware EngineerMaximum Profit from One Stock Purchase and a Later Sale
This problem tests the ability to solve the 'best time to buy and sell stock' pattern in O(n) time and O(1) space, identifying the minimum price seen so far to calculate potential profit.
Coding & AlgorithmsTechnical ScreenArraysGreedyOptimization - XiaopengMediumSoftware EngineerMaintain the Median of a Data Stream
This problem tests the ability to maintain dynamic statistics in a data stream using efficient data structures to achieve optimal insertion and retrieval times.
Coding & AlgorithmsTechnical ScreenHeapsData StreamsSorting - YahooMediumData ScientistMerge words by head-tail chaining
This question evaluates graph-theoretic reasoning and string-manipulation skills, focusing on the ability to reason about ordering constraints, edge cases like self-loops and multiple identical relationships, and traversal over relationships between items.
Coding & AlgorithmsTechnical Screen - YahooEasyMachine Learning EngineerRank Items by Dot-Product Similarity to a User Embedding, Excluding Seen Items
Rank candidate items for a user by the dot product of the user's embedding with each item's embedding, returning item indices from highest to lowest score with ties broken by index. A follow-up removes items the user has already seen, testing vectorized scoring, sorting and filtering.
Coding & AlgorithmsTechnical Screen - YahooMediumData ScientistSolve Data Structure Challenges with Python Algorithms
This question evaluates proficiency in fundamental data structure manipulation and string-processing algorithms, specifically preserving insertion order during list deduplication and performing iterative overlap-based word merging.
Coding & AlgorithmsTechnical Screen - YelpEasyData ScientistReturn Integers in Descending Ranked Order
This problem tests the ability to manipulate lists and sort data while maintaining the relative order of duplicate elements using common programming patterns.
Coding & AlgorithmsTechnical ScreenSortingArraysAlgorithms - ZillowMediumMachine Learning EngineerImplement k-th largest in a number stream
This question evaluates proficiency with data structures and order-statistics in a streaming context, focusing on API design and time/space complexity trade-offs within the Coding & Algorithms domain.
Coding & AlgorithmsTechnical Screen - ZillowMediumMachine Learning EngineerImplement placeholder-based pattern matcher
Implement placeholder-based pattern matcher 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 - ZipHQMediumSoftware EngineerCompute maximum sum in a tree without adjacency
This question evaluates dynamic programming on trees and graph component identification by requiring selection of non-adjacent nodes to maximize a sum, targeting skills in tree algorithms, constraint-based optimization, and rigorous correctness and complexity reasoning.
Coding & AlgorithmsTechnical Screen - ZipHQMediumSoftware EngineerFind root IDs and paths
This question evaluates understanding of graph/tree relationships, identification of root nodes, and path reconstruction from parent references, assessing algorithmic reasoning and data-structure familiarity.
Coding & AlgorithmsTechnical Screen - ZipHQHardSoftware EngineerFind the Guaranteed Capture Time in a Turn-Based Graph Game
Solve guaranteed capture time in a finite turn-based graph pursuit game, including Jerry-first moves, staying, optimal adversarial play, and infinite evasion on cycles.
Coding & AlgorithmsTechnical Screen - ZipHQMediumSoftware EngineerMaximize non-adjacent sum on an N-ary tree
This question evaluates skills in tree-based dynamic programming, recursive traversal, and per-node state management for selecting non-adjacent nodes in an N-ary tree.
Coding & AlgorithmsTechnical Screen - ZiplineMediumSoftware EngineerImplement a Maximum-Tracking Stack
This question evaluates competency in data structure design and algorithmic analysis, focusing on stack operations augmented with maximum-tracking and correctness when multiple maximal elements and ordering constraints are present.
Coding & AlgorithmsTechnical Screen - ZiprecruiterEasyMachine Learning EngineerFind Neighboring Records by Identifier
This question tests the ability to manage ordered sequences and perform O(log n) lookups to retrieve adjacent elements in a dataset.
Coding & AlgorithmsTechnical ScreenBinary SearchArraysEfficiency - ZooxMediumMachine Learning EngineerCompute Roller Coaster Scores
Tests string parsing, floating-point evaluation, conditional logic, and the implementation of an extensible rule-based scoring engine for ride telemetry.
Coding & AlgorithmsTechnical ScreenString ParsingImplementationDesign Patterns - ZooxMediumSoftware EngineerLane-Change Safety and Longitudinal Motion Simulation
Implement a discrete-time kinematic simulator to evaluate whether an autonomous vehicle can safely execute a lane change given adjacent lead and lag vehicles.
Coding & AlgorithmsTechnical Screensimulationkinematicsautonomous-vehicles - ZooxMediumSoftware EngineerThree Array Problems for Trading Geometry and Grouping
Implement three foundational utility functions for an algorithmic trading log analyzer: maximum single-transaction profit, detection of four collinear price points, and deterministic equivalence grouping of trader nicknames.
Coding & AlgorithmsTechnical ScreenArrayGeometryUnion Find - ZooxMediumData EngineerWrite Transaction Analytics SQL Queries
This question evaluates proficiency in SQL for analytical queries, covering aggregation, time-based filtering, joins between transactions and vendor metadata, and the use of ranking/window functions for top-N calculations.
Coding & AlgorithmsTechnical Screen
Whatnot
XPeng
Yahoo
ZipHQ
Zipline
Zoox