Waymo coding interview

Questions Waymo asks in this round 34

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  2D max pooling that also returns where each maximum came fromCodingImplement 2D max pooling over a grid of integers: a k by k window moves across the grid with a given stride, and each window outputs its maximum. Follow-up: for every output cell…

  Last asked Sep 2026Were you asked this too?
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  Autocomplete search bar with a hand-written debounceCodingBuild an autocomplete search bar: as the user types, show suggestions for the current text, fetched from a suggestion service. Calls must be debounced, so the service is called…

  Last asked Sep 2026Were you asked this too?
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  Count squares formed by vertical and horizontal segmentsCodingYou get a set of vertical and a set of horizontal line segments. Every point where a vertical and a horizontal segment cross or touch is an intersection. Count the squares whose…

  Last asked Sep 2026Were you asked this too?
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  Filter an n-ary tree by substring and render it indentedCodingEach node of an n-ary tree has a string value and a list of children. 1. Given a search string, return the filtered tree: keep every node whose value contains the substring, plus…

  Last asked Sep 2026Were you asked this too?
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  Insert plus, times and parentheses to reach a targetCodingYou are given an equation whose left side is a sequence of non-negative integers with no operators between them, and whose right side is a target. For example: 2 3 4 = 20. Insert…

  Last asked Sep 2026Were you asked this too?
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  Is a number line fully covered after each landing point?CodingPoints land one at a time on the segment 0, 50. Each point covers the interval of length 1 centred on it (0.5 to each side), and covered parts stay covered. After each landing…

  Last asked Sep 2026Were you asked this too?
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  Link object tracks across two perception systemsCodingTwo perception systems, A and B, track the same objects around a vehicle independently, each with its own IDs, and each emits observations of its tracks over time. Implement an…

  Last asked Sep 2026Were you asked this too?
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  Character at an index of a run-length encoded stringCodingA string is stored run-length encoded, like "B1A2E3C1" for BAAEEEC. Return the character at a given index without decoding the string. Follow-up: many queries; precompute prefix…

  Last asked Sep 2026Were you asked this too?
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  Copy a rectangle within a 2D array in placeCodingGiven a 2D array, a rectangular block (top-left corner, height, width) and a destination for its top-left corner, copy the block to the destination with O(1) extra memory. The…

  Last asked Sep 2026Were you asked this too?
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  Custom sort stringCodingGiven an order string of distinct letters and a string s, rearrange s so its letters follow the order given; letters missing from order may go anywhere. Count letters and emit…

  Last asked Sep 2026Were you asked this too?
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  Deduplicate a 256 GB file with 128 MB of memoryCodingA 256 GB file holds records, some duplicated. The machine has 128 MB of memory. Produce output that holds every distinct record exactly once. Explain the approach (for example…

  Last asked Sep 2026Were you asked this too?
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  Does a seven-segment display read the same rotated 180 degrees?CodingAn LED display shows a row of digits on seven-segment cells. Decide whether the display reads exactly the same after rotating it by 180 degrees. Work out which digits map to which…

  Last asked Sep 2026Were you asked this too?
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  Drive to an unseen destination without going in circlesCodingA car must reach a destination on a map it cannot see in advance. Each time it arrives at a place, it learns which directions it can continue in from there. Write the search that…

  Last asked Sep 2026Were you asked this too?
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  Lowest horizontal line that splits squares into equal areasCodingSeveral axis-aligned squares are given by their bottom-left corner and side length. Find the lowest horizontal line y = h such that the total square area below the line equals the…

  Last asked Sep 2026Were you asked this too?
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  LRU cacheCodingBuild a key-value cache with a fixed capacity that evicts the least recently used entry when it is full. get(key) returns the value or a miss, put(key, value) inserts or updates…

  Last asked Sep 2026Were you asked this too?
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  N-th number whose digits are all 3, 5 or 6CodingA good number is a positive integer whose decimal digits are all 3, 5 or 6: 3, 5, 6, 33, 35, 36, 53, ... Given n, return the n-th good number. Notice the link to counting in base…

  Last asked Sep 2026Were you asked this too?
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  Parse a raw CSV string and handle corrupted rowsCodingAnother team receives data as a raw CSV payload in one string. Write code that turns it into a data structure other teams can consume. Some rows are corrupted (wrong number of…

  Last asked Sep 2026Were you asked this too?
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  Predict the winner of a pick-from-either-end gameCodingTwo players take turns removing a number from either end of an array and adding it to their score; player 1 moves first and both play optimally. Return whether player 1 can win (a…

  Last asked Sep 2026Were you asked this too?
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  Return every word that starts with a prefixCodingBuild a structure over a word list, once, that answers many prefix queries: for a prefix, return every word in the list that starts with it, without rescanning the whole list. A…

  Last asked Sep 2026Were you asked this too?
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  Softmax cross-entropy forward and backward, then a training loopCodingImplement from scratch, with NumPy but no autograd, the forward and backward pass of a softmax layer followed by cross-entropy loss. Keep it numerically stable. Then use it in a…

  Last asked Sep 2026Were you asked this too?
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  Sort a transformed arrayCodingGiven a sorted array and the coefficients a, b, c of f(x) = ax^2 + bx + c, apply f to every element and return the results in sorted order in O(n). Use two pointers from both…

  Last asked Sep 2026Were you asked this too?
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  Shortest distance from all buildingsCodingA grid has empty land, buildings and obstacles. Find the empty cell whose total walking distance to every building is smallest (moving up, down, left or right), or return -1 if no…

  Last asked Aug 2026Were you asked this too?
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  Format bytes as a hex and ASCII dumpCodingWrite a function that prints a byte buffer as a hex dump, like xxd or hexdump -C: each line shows the offset, a fixed number of bytes in hex, and the same bytes as ASCII with…

  Last asked Aug 2026Were you asked this too?
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  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 2026Were you asked this too?
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  Find dictionary words that stretch into a given stringCodingA word can produce a string by repeating some of its letters in place: help can produce heellp. Given the string and a dictionary, return every dictionary word that could produce…

  Last asked Jun 2026Were you asked this too?
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  Debug an Angular UI from user reportsCodingYou get an Angular application and a handful of user bug reports. Reproduce each problem, find the cause in the code and fix it, explaining how you narrowed it down.

  Last asked May 2026Were you asked this too?
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  Run promise tasks with bounded concurrencyCodingGiven a list of async tasks (functions returning promises) and a limit k, run them with at most k in flight at once, start the next as soon as one finishes, and resolve with all…

  Last asked May 2026Were you asked this too?
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  Largest axis-aligned rectangle from pointsCodingYou are given a list of distinct points on a 2D integer grid. Each point is a pair x, y. Return the largest area of a rectangle whose sides are parallel to the x and y axes and…

  Last asked Apr 2026Were you asked this too?
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  Jump gameCodingEach element of an array is the maximum jump length from that position. Starting at index 0, decide whether you can reach the last index. Solve it greedily in O(n) by tracking the…

  Last asked Feb 2026Were you asked this too?
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  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 2026Were you asked this too?
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  Average speed at a point on a road with overlapping reportsCodingA straight road is modeled as the number line from position 0 to 10^9. Vehicles send speed reports. Each report says that traffic on the half-open segment start, end) moved at…

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  Garage occupancy at every timestampCodingA parking garage records occupancy over n discrete timestamps, numbered 0 to n - 1. You get a list of parking tickets. Ticket entry, exit means one car arrived at timestamp entry…

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  Minimum workers with first-free job assignmentCodingJobs arrive as (jobid, start, end) with half-open times start, end). Workers are numbered 0, 1, 2, ... Part 1. Process jobs by start time (ties by job id). Each job goes to the…

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  Score a tile board by connected terrain regionsCodingA tile-laying board game ends when every player has filled a rectangular board. You must compute a player's final score. You are given board, a 2D list of strings with R rows and…

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