Game of Life on a grid too big for memoryCodingStarting from working Game of Life code, adapt it to a grid stored on disk that cannot be loaded at once, using given file helpers. Keep next-generation semantics exact, including…
Last asked Oct 2026
#simulation
Split-tender payments with gift cards, surcharges and refundsCodingAt a retail point of sale one purchase can be paid with several methods, for example part on a gift card and the rest on a credit card (a split-tender transaction). Write the code…Last asked Oct 2026
Microorganisms eating neighbours: the largest survivorCodingMicroorganisms stand in a row. Each one has a family (a letter) and a size (a positive integer). A microorganism can eat the neighbour directly to its left or right when that…Last asked Oct 2026- Fault-tolerant work queue with leases and retriesCodingImplement an in-memory work queue that keeps working when workers crash. Workers take a task, process it, and report success or failure. A worker that dies silently must not lose…Last asked Oct 2026
- Route requests to the nearest healthy data centerCodingBuild a router that processes commands: register a data center with its latitude, longitude and capacity, mark data centers up or down, report the great-circle distance between…Last asked Sep 2026
2048 game with move, merge and game-over detectionCodingImplement the 2048 game loop: board moves with tile merging, spawning new tiles, and detecting when no move remains. Reported on 1point3acres' Glean bank; reconstructed in our own…Last asked Sep 2026
+1Connect Four game engine with win detectionCodingImplement a two-player game of Connect Four. The board has rows rows and cols columns (default 6 x 7). Players "A" and "B" alternate turns, and "A" moves first. On a turn, a…Last asked Sep 2026- +3Threshold infection spread on a gridCodingA lab tracks a disease across a rectangular field of cells. You are given an m x n grid where 0 is a healthy cell and 1 is an infected cell, and an integer threshold. Each day…Last asked Sep 2026
- Three-card showdown between two playersCodingDesign a two-player card game that uses a standard 52-card deck. Each card has a rank and a suit. From lowest to highest, the ranks are 2 3 4 5 6 7 8 9 10 J Q K A. The suits are C…Last asked Sep 2026
Reversi move simulation with captures in 8 directionsCodingImplement one move of the board game Reversi (also sold as Othello). You get an n x n board as a list of lists of characters. Each cell is 'B' (black), 'W' (white) or '.' (empty)…Last asked Sep 2026
+1Task manager with user quotas and expiring assignmentsCodingBuild an in-memory TaskManager in four levels. Each level adds methods to the same class, and you move to the next level only after the current one passes. Every method takes an…Last asked Sep 2026
Can every car park with preferred spots and forward-only overflowCodingA one-way street has n spots numbered 0 to n - 1. Cars arrive in order; car i wants spot preferencesi, takes it if free, and otherwise drives forward to the next free spot. A car…Last asked Sep 2026- Hotel stay email schedule with booking changesCodingA hotel wants to send each guest a set of emails around their stay. Write the code that produces the full email schedule. Input - reservations: a list of objects with guestname…Last asked Sep 2026
Four in a row: check a winning moveCodingTwo players, "a" and "b", play on a rectangular grid. board is a 2D list of strings; each cell is "a", "b", or "" (empty). Implement: move = (row, col) is the cell where player…Last asked Sep 2026- Memory allocator: leftmost free block and free by ownerCodingA memory has n units, numbered 0 to n - 1, all free at the start. Process a list of operations in order, each producing one recorded value: 1. Allocate size units for an owner:…Last asked Sep 2026
+1Generalized tic-tac-toe with k in a rowCodingDesign a two-player Tic-Tac-Toe game on a board with n rows and m columns. A player wins by placing k of their own marks consecutively in one line: horizontal, vertical, diagonal…Last asked Sep 2026- Text box formatterCodingImplement formatboxes(sentences: liststr) - liststr. Each sentence is a non-empty string of printable ASCII characters and spaces. Draw every sentence in its own ASCII box and…Last asked Sep 2026
- Financial account ledger with acceptance, limits and settlementCodingImplement processledger(commands), which handles commands in order: set up accounts, request deposits and query balances. Return the query answers as one comma-separated string…Last asked Sep 2026
Design simulation infrastructure to evaluate a self-driving model on limited computeSystem designStart from an open question: how would you evaluate a self-driving model? Then design the infrastructure: running thousands of simulations when there is not enough compute…Last asked Sep 2026
Sort a grid into snake order with adjacent swapsCodingAn n x n board holds each number from 1 to nn once. Rearrange it into snake order: the first row increases left to right, the second right to left, and so on, alternating. The…Last asked Sep 2026- +2Cloud storage with user quotas and backupsCodingDesign an in-memory cloud storage service. The interview has four parts. Each part adds methods, and every earlier method must keep working. Implement a class CloudStorage. File…Last asked Sep 2026
Most visited position on a circular trackCodingA race runs over a circular track of numbered sections, given as the order of sections it passes through. Return the section or sections visited most often. Only the title of this…Last asked Sep 2026
Design an autonomous-vehicle simulatorSystem designDesign a simulation system for testing self-driving software: how scenarios are defined, how the vehicle software runs against simulated sensors and other actors, how many…Last asked Aug 2026- +1Shuffle, deal and sort a four-player card handCodingYou are building the core of a four-player card game. Model a standard 52-card deck and implement the deal. Types to define - Suit: CLUBS, DIAMONDS, HEARTS, SPADES, in this order…Last asked Aug 2026
- +1Turn-based monster team battle simulatorCodingWrite a deterministic simulator for a turn-based battle between two ordered teams of monsters, and return the battle log and the result. python class Monster: name: str unique…Last asked Aug 2026
- +1Shift grants with promotions that start next entryCodingTrack workers clocking in and out, apply promotions starting from the next office entry, and total granted bonuses across overlapping work sessions. - Level 1: addworker(id…Last asked Aug 2026
- Minesweeper: reveal a regionCodingImplement a click on a Minesweeper board. Clicking a mine ends the game. Clicking a cell with mines around it shows the count. Clicking a cell with none reveals it and spreads to…Last asked Aug 2026
- Fill an order from the oldest inventory batches firstCodingA warehouse keeps stock in batches received at different times. Fill an order by taking units from the oldest batches first, moving to newer batches as each one runs out. Return…Last asked Aug 2026
- Repair a looping bootloader programCodingA tiny bootloader stores its program as a list of text instructions. Each entry has the form "<op <value", where value is a signed integer. The machine has one accumulator, which…Last asked Jul 2026
- Find a repeating command program for a vehicle under fuel and memory limitsCodingA vehicle on a grid starts at a given cell with 100 fuel. Each move up, down, left or right costs one unit; at a station it can refuel 50 units; obstacles block movement. It can…Last asked Jun 2026
- Step a set of moving vehicles until the first collisionCodingEach vehicle is a circle with a position, heading, constant speed and turn rate. Advance them in small fixed time steps and stop at the first time two of them touch, reporting…Last asked Jun 2026
+1Caesar cipher with wraparound shiftsCodingImplement caesarencrypt(text: str, k: int) - str, which applies a Caesar cipher to text. Every ASCII letter moves k places forward in the alphabet. The alphabet is circular, so a…Last asked Jun 2026- Allocate inventory by bid priorityCodingAllocate a limited inventory across a set of bids, serving the bids in priority order, and report what each bid receives.Last asked Jun 2026
- Asteroid collisionCodingAsteroids move along a line; each has a size and a direction. When two meet, the smaller one explodes, and both explode if they are the same size. Return the asteroids left after…Last asked Jun 2026
- Maximum candies from boxes with keysCodingSome boxes are open and some are locked. Each box holds candies, keys to other boxes, and more boxes. You start with a few boxes. You may open a box once you have it and it is…Last asked May 2026
- Per-position feedback for a guess against a secret wordCodingGiven a secret word and a guess of the same length, return feedback for each position of the guess, Wordle style: the letter is in the right place, is in the word but elsewhere…Last asked May 2026
- Account balances from a transaction logCodingA payments system receives a log of transactions and must turn it into account statements. Each log entry is a string with four comma-separated fields: - transactionid: a unique…Last asked May 2026
- Knockout tournament by rank, then build the bracketCodingPlayers are listed by rank, where a smaller number is a better player. Neighbours play each other (index 0 against 1, 2 against 3, and so on) and the better rank advances, round…Last asked May 2026
Game of Life, updated in placeCodingEach cell of a grid is alive or dead, and all cells update together from the states of their eight neighbors, as in Conway's Game of Life. Compute the next state in place, without…Last asked May 2026- Turnstile crossing timesCodingPeople arrive at a single turnstile at given times, each wanting to enter or to exit, and one person passes per second. When people going both ways are waiting, a priority rule…Last asked May 2026
- Refund allocation across prioritized payment methodsCodingA customer's order was paid with one or more payments, and some of them may already have been partly refunded. Implement a function that splits a new refund across those payments…Last asked Apr 2026
- Deduplicate account sign-ups by email and phoneCodingA sign-up service processes account registrations one at a time, in the order they arrive. You get three lists of the same length n: names, emails and phones. Index i of each list…Last asked Apr 2026
- Lexicographically largest output from a spreading availability maskCodingA test-data service builds an output array S from two inputs: - arr, an array of n positive integers; - state, a string of length n made of '0' and '1'. statei = '1' means arri is…Last asked Apr 2026
+1Spiral matrixCodingReturn all elements of an m x n matrix in spiral order: along the top row, down the right column, back along the bottom row, up the left column, then inward.Last asked Apr 2026- CPU microarchitecture and simulator designCodingFor a CPU architect role: read and reason about assembly code; explain microarchitecture parts such as branch predictors, the MOESI coherence protocol, caches and MSHRs, VIPT…Last asked Mar 2026
- Research OA: best value ratio, shuttle trips and grid commandsCodingA multi-part online assessment. 1. Given ratings and prices, return the index with the highest rating-to-price ratio, choosing the smaller index on ties. Compare the fractions…Last asked Mar 2026
- Rotting oranges: time for an infection to cover a gridCodingA grid has empty cells, healthy cells and infected cells. Every minute each infected cell infects its healthy neighbors up, down, left and right. Return the minutes until no…Last asked Mar 2026
Courier pay from order eventsCodingA delivery courier is paid for active time. You receive the events of their orders (for example accepted and delivered, with timestamps) as if from an upstream service. Compute…Last asked Mar 2026- Busiest meeting room after simulated bookingsCodingSimulate booking meetings into a fixed set of rooms and return the room that held the most meetings. Agree on the rules first: which free room a meeting takes, and what happens to…Last asked Mar 2026
Update a grid of firing neuronsCodingA grid holds neurons that are either firing or not. In each step every neuron's next state depends on how many of its neighbours are firing, in the style of the Game of Life…Last asked Feb 2026- Simulate particles from a point source hitting a screenCodingA point source sits some distance in front of an infinitely tall vertical screen and fires particles toward it. Each particle leaves at a random angle drawn uniformly between -π/2…Last asked Feb 2026
- Most coins collected by tokens that jump three cellsCodingA one-player board game: a string of N positions, each empty (.), holding one of the player's tokens (T) or holding a coin (C). The player may have several tokens, and a token…Last asked Feb 2026
- Sticky load balancer for long-lived connectionsCodingSimulate a load balancer that routes long-lived WebSocket connections to several Jupyter servers. Process a sequence of requests such as CONNECT, DISCONNECT and SHUTDOWN: place…Last asked Feb 2026
- Lift-to-stairs switch with an energy budgetCodingYou start on floor 0 of a building with 0 energy and need to reach floor n. You ride the lift from floor 0 up to some floor k (0 <= k <= n), then walk the stairs from floor k to…Last asked Feb 2026
- Modeling other agents in a driving simulatorML designIn a simulator used to test a self-driving stack, how do you model the other agents (cars, pedestrians, cyclists)? Compare replaying logged behavior, rule-based agents and learned…Last asked Feb 2026
- Time for a virus to infect the whole gridCodingA grid has infected, healthy and empty cells. Each minute the virus spreads from every infected cell to its healthy neighbours up, down, left and right. Return the number of…Last asked Feb 2026
- Diagonal traversal of a matrixCodingReturn the elements of a matrix diagonal by diagonal. In one version the direction alternates (up-right, then down-left); in another every diagonal is read in the same direction…Last asked Feb 2026
- Pour water onto a terrainCodingAn array gives the height of each column of a terrain. 1. Print the terrain. 2. Drop a given number of water units at a column, one at a time. Each unit moves left if it can…Last asked Feb 2026
- Design a simulator that replays recorded left-turn scenariosSystem designDesign a simulator that takes recorded videos of real left turns and replays them as scenarios, so an autonomous-driving stack can be tested against what actually happened on the…Last asked Feb 2026
- Backend for a game of checkersCodingBuild the backend of a checkers game under time pressure: board state, legal moves, captures and the win condition, with a data model you can explain. A working core matters more…Last asked Feb 2026
- Place Tetris-like shapes in the first spot that fitsCodingYou have an n x m grid and a sequence of shapes from a small fixed set. Place the shapes one at a time, in order; each goes into the first position where it fits, scanning rows…Last asked Feb 2026
- Move instructions for a robot that cannot see the mazeCodingA robot is in a 2D maze but cannot see it. Produce the sequence of move instructions that gets it to the goal, under the rules the interviewer gives for what happens when a move…Last asked Jan 2026
- Card authorization report with fraud rulesCodingA payment platform receives authorization requests: a card holder's intent to pay a merchant. Write a function that decides each request and returns a report. Each request is a…Last asked Jan 2026
- Alert trigger and resolve events from merchant error logsCodingYou get transaction logs with timestamp, merchantid, statuscode and count. For each (merchantid, statuscode) pair, emit a TRIGGER event when that error's count over a recent time…Last asked Jan 2026
- Robot charging controller with exclusive stationsCodingA fleet of robots shares a small number of charging stations. A robot whose battery drops below 50% should go to a free station, and a robot charging above 95% may leave and go…Last asked Jan 2026
- Meeting rooms with delayed starts: the busiest roomCodingThere are n rooms numbered from 0 and a list of meetings with distinct start times. Each meeting takes the free room with the lowest number; if none is free, it waits for the…Last asked Jan 2026
- Least-loaded task assignment with worker specialtiesCodingTasks arrive in a fixed order and must be handed out to a team of workers so that the work stays balanced. Each task has a unique integer id, a positive integer duration, and (in…Last asked Jan 2026
- Smallest starting index that never leaves on the leftCodingEach cell of an array holds a move: a positive number moves you that many cells right, a negative one moves you left. Starting from some index you keep following the moves. Find…Last asked Dec 2025
- Four short array and string exercisesCodingFour quick problems in one round: 1. Return the difference between the number of uppercase and lowercase letters in a string. 2. Repeatedly subtract from the non-zero elements of…Last asked Dec 2025
- Collect coins with tokens that move three steps rightCodingA one-row board is a string of . (empty), T (a token) and C (a coin). A move takes any token exactly three cells to the right, onto a cell no token occupies; landing on a coin…Last asked Dec 2025
- One round of candy crush on a gridCodingAn integer matrix holds coloured blocks; equal numbers are the same colour and 0 is empty. Run one round: find every block that is part of a group to crush (clarify the rule; the…Last asked Sep 2025
- Automatic emergency braking logic in PythonCodingWrite a simple automatic braking function in Python: given the vehicle's state and what is ahead of it (for example speed and distance to an obstacle), decide whether and how hard…Last asked Sep 2025
- Place fixed shapes on a grid in orderCodingYou get an n x m grid and a list of shapes, like Tetris pieces that neither rotate nor fall. Place them in order: each goes at the first position, scanning from the top-left…Last asked Sep 2025
- Fleet capacity after server id replacementsCodingA service runs on a fleet of n servers. Each server has an integer id, and a server with id x can handle x requests at a time. The fleet's total capacity is the sum of all server…Last asked Sep 2025
- Rank vehicles by peer-to-peer update contributionCodingA fleet of electric vehicles receives over-the-air software updates split into fixed-size chunks. Chunks come from the distribution server over cellular data, which is expensive…Last asked Jul 2025
- Inventory allocation with backordersCodingOrders arrive for products whose stock is limited. Allocate stock to orders as they come in; when a product runs out, record the unfilled part as a backorder and fill backorders…Last asked Jul 2025
- Alert routing service with silences and escalationCodingBuild the routing core of an alerting service. The monitoring system calls fire(labels, now) for an active alert on every evaluation cycle (every 30 seconds or so) and…
Design an evaluation harness for a customer-support AI agentAI system designA company's AI agent answers its customers over chat and takes actions through tools (refunds, plan changes, escalations). Every prompt, model, tool or policy change can break it…- Disk block writes with limited write cyclesCodingA storage device has n blocks with ids 0 to n - 1. Every block can be written at most maxcycles times; after that it is worn out and can never be written again. Implement a…
- Dot grid game winnerCodingTwo players play a dots-and-boxes style game on a 9 x 9 grid of dots. The grid has 8 x 8 = 64 unit squares ("boxes"). Rows and columns are numbered 0 to 8. You are given moves, a…
- Process queue with wait limitsCodingA single server works through a line of n processes in first-in, first-out order. Process i (0-indexed, in line order) can wait at most waiti seconds. Once that much time has…
- Pascal triangle digit encryptionCodingDigits are encrypted by folding them down an upside-down Pascal's triangle. You get a list of n digits (each 0-9). In one round, replace the list with the sums of each pair of…
- Place books on the least-full allowed shelfCodingYou have numshelves shelves, numbered 0 to numshelves - 1. All shelves start empty. Books arrive one at a time. Book i comes with a limit limitsi. It may only go on shelves 0…
- Fuel station queue with three dispensersCodingA fuel station has three dispensers named X, Y and Z. Each starts with a known number of liters. A queue of cars waits at the station, and all of them are in line at time 0. Car i…
- Justify articles to a fixed line widthCodingYour platform shows articles in a fixed-width text column. Write a function that lays out a list of articles and returns every output line in order, as one flat list. Rules - Each…
- Spell a word on a 5-column letter boardCodingA text-entry device shows the 26 lowercase letters on a board 5 columns wide, filled row by row. Letter c sits at row (ord(c) - ord('a')) // 5 and column (ord(c) - ord('a')) % 5:…
- Red and black tile slides and jumpsCodingA strip of cells holds red tiles (R), black tiles (B) and empty cells (). The board is a string such as "RRBB". Movement rules - A red tile only moves right. A black tile only…
- Route a request along diagonal server redirectsCodingServers sit at distinct integer points on an infinite 2D grid. locationsi = x, y is the position of server i. A request starts at server 0, which counts as visited. You are given…
- Connect Four board with gravity drops and board snapshotsCodingBuild the board for a gravity-based four-in-a-row game. Players drop single-character colored pieces into columns. A piece falls straight down and stops in the lowest empty cell…
- Two-player card game simulationCodingYou are building the engine for a simple two-player card game. Players are named "A" and "B". The deck is a list of distinct integers, and a higher integer beats a lower one…
- Valid date from three integers in any orderCodingYou are given three integers a, b and c. Their order is unknown: any one of them may be the year, the month or the day. This covers formats such as yyyy-MM-dd, MM-dd-yyyy and…
- Server load scores from a day of requestsCodingA load balancer team wants a daily stress report for its server fleet. You get three inputs for one day: - servers: lines serverid,basescore. Every server starts at its integer…
- Collatz sequence steps with memoized range maximumCodingStarting from a positive integer n, repeat the following until n equals 1: - If n is even, set n = n / 2. - If n is odd, set n = 3n + 1. Each replacement counts as one step. (It…
- Finish times for round-robin tasksCodingA single worker processes a list of tasks. Task i needs arri hours of work in total. The tasks wait in a queue in index order. Each turn, the worker takes the task at the front…
- +1Cake order fulfillment checkCodingA bakery keeps three kinds of cake. Its stock is an array stock of length 3, where stocki is how many cakes of type i are on hand. Orders arrive one at a time in the list orders…
- ATM queue exit orderCodingThere are n people waiting in a single line at an ATM. They are numbered 1 to n from the front of the line to the back. You are given an integer array amounts, where amountsi is…
- Drop a Tetris piece and clear full rowsCodingImplement a single step of a Tetris-like game. You get three inputs: - background: an H x W grid of 0/1. 1 is an occupied cell, 0 is empty. Row 0 is the top. - block: an h x w…
- Poker hand checker with jokersCodingWrite isvalidhand(hand: liststr) - bool for a five-card poker game. Each card is a string "<rank of <suit". The rank is 2 to 10, J, Q, K or A. The suit is hearts, diamonds, clubs…
Apply ordered token merges to a stringCodingMany language models read text as a list of token ids. In this scheme, every token after the single characters is built from two earlier tokens, and turning text into ids means…