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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 3181–3210 of 3276 results
- WaymoMediumSite Reliability EngineerIs the Segment From 0 to 50 Fully Contaminated After Each Landing Point?
Points land one at a time on the segment from 0 to 50, each contaminating an interval of length 1 around it; after each landing, report whether the whole segment is contaminated. Tests interval union maintenance, exact boundary handling and efficient updates.
Coding & AlgorithmsOnsite - WaymoMediumSoftware EngineerLowest Horizontal Cut That Splits Square Cakes Into Equal Total Areas
Square cakes sit on a table with sides parallel to its edges; find the lowest horizontal cut line that splits the total cake area equally, returned as an exact fraction. Tests sweeping over heights, piecewise-linear area accumulation and exact arithmetic.
Coding & AlgorithmsOnsite - WaymoMediumSoftware EngineerMinimize Total Grid Distance to Every Building
Find an empty land cell in a 2D grid that minimizes the sum of shortest travel distances to all buildings without traversing through obstacles or other buildings.
Coding & AlgorithmsOnsiteBreadth-First SearchMatrixShortest Path - WaymoMediumMachine Learning EngineerReturn All Words Matching Each Prefix From a Word List
Build a structure over a word list that answers prefix queries, returning every distinct word that starts with each prefix in lexicographic order. Tests prefix-tree design, deduplication, and answering many queries without rescanning the whole list.
Coding & AlgorithmsOnsite - WaymoMediumData ScientistSample Points Uniformly from a Unit Disk
Derive uniform random sampling inside a unit disk, explain the radial distribution, and compare a polar sampler with rejection sampling.
Coding & AlgorithmsTechnical Screen - WaymoMediumSoftware EngineerSort the Results of Applying a Quadratic Function to a Sorted Array
Apply the quadratic function a*x*x + b*x + c to every element of a sorted integer array and return the results in sorted order, where a may be negative or zero. Tests reasoning about the parabola's shape and merging values from both ends in linear time.
Coding & AlgorithmsOnsite - WaymoMediumSoftware EngineerValidate a Parent-Child Forest
This problem tests graph theory fundamentals by requiring the validation of a forest structure, specifically checking for cycle-free properties and valid parent-child node connectivity constraints.
Coding & AlgorithmsTechnical ScreenGraph TheoryDFSDSU - WeRideMediumSoftware EngineerExpand algebraic expression with distribution
This question evaluates parsing of algebraic expressions, application of the distributive law, string manipulation, and algorithmic reasoning about time and extra-space complexity.
Coding & AlgorithmsTechnical Screen - WeRideMediumSoftware EngineerImplement Several Core Algorithmic Components
This problem tests your ability to implement fundamental algorithms, including caching mechanisms, probability transformations, and geometric counting patterns.
Coding & AlgorithmsTechnical ScreenHashMapsLinked-ListsProbability - WeRideMediumSoftware EngineerImplement expression expansion to plus-only form
This question evaluates understanding of expression parsing and algebraic expansion via the distributive property, along with skills in string manipulation, stack-managed state for nested parentheses, and time/space complexity analysis.
Coding & AlgorithmsTechnical Screen - WeRideMediumSoftware EngineerImplement matrix multiplication and fast exponentiation
This question evaluates competency in matrix multiplication, modular arithmetic, and exponentiation algorithms as applied to large-scale numeric computations such as sequence generation.
Coding & AlgorithmsTechnical Screen - WeRideMediumSoftware EngineerValidate Bracket Sequence
This problem tests the ability to manage nested structures using a stack to ensure that all opening brackets are closed in the correct order and type.
Coding & AlgorithmsOnline AssessmentStackStringData Structures - WhatnotHardSoftware EngineerBuild User Journey Path Summary
This question evaluates the ability to transform unordered user action logs into a trie-like path tree, exercising skills in grouping and time-sorting per user, maintaining stable insertion order, counting distinct users per prefix, and producing deterministic preorder string output.
Coding & AlgorithmsTechnical Screen - 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 - WhatnotEasySoftware EngineerCount User Journey Prefixes
Process timestamped user activity logs to reconstruct chronological action sequences and count the frequency of user journey prefixes up to length k.
Coding & AlgorithmsOnline Assessmenthash-mapsortingstrings - 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 - WorkdayMediumSoftware EngineerBuild a Fuzzy Keyword Index
This problem tests your ability to design an efficient data structure for performing fuzzy keyword lookups using edit distance constraints on a static corpus of strings.
Coding & AlgorithmsOnsiteStringsTrieHash Map - WorldquantMediumSoftware EngineerCount Unordered Combinations of Unlimited Coins
Count distinct ways to reach a target with unlimited coins, treating different orders of the same denominations as one combination.
Coding & AlgorithmsOnline Assessment - 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
Waymo
WeRide
Whatnot
Worldquant
XPeng