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Practice coding, system design, behavioral, and project questions for frontier AI roles.
Every question has a public brief with the task, constraints, and follow-ups. Labels describe interactive practice access.
Reported interview periodNot available
One behavioral story about a disagreement you did not drop.
Practice focusBehavioral round. Tell one story about a disagreement you did not drop. Name the date, the decision, the other person's concern, the sentence you said, and what you changed. Then say what you refused to change, and how you knew the work was still safe. Stay on that one story.
Reported interview periodNot available
A culture conversation about a promise the team now wants to change.
Practice focusCulture round. A user was told one thing, and the team now wants to ship something else. Say what the user was told, what would change, and who you would tell before the change ships. Then the interviewer says the change is already approved. Name the person you would still tell, and the sentence you would use.
Reported interview periodNot available
A recruiter conversation that stays on one piece of work and one skill to learn.
Practice focusRecruiter round, two minutes. Pick one piece of work. Who needed it. What you did yourself. Which skill carries. Then name one thing you would learn in the first month, and how you would know you had learned it.
Reported interview periodNot available
One behavioral story about a decision made when the facts were thin.
Practice focusBehavioral round. Tell one story about a decision you owned when the facts were thin. When it was. What you knew. What you did not know. The call you made. Who you told. What happened after. Stay on that one story.
Reported interview periodNot available
A culture conversation about a limit you set on a piece of work.
Practice focusCulture round. Name a limit you set on a piece of work. What the work was. Who asked you to go past the limit. What you said. What you offered instead. Then say how you would check, a week later, that the limit still held.
Reported interview periodNot available
A recruiter conversation that stays on one run you owned.
Practice focusRecruiter round, two minutes. One run you owned. Who it was for. The constraint. What you did with your own hands. The skill that transfers. One skill you would learn in the first month.
Reported interview periodNot available
Prepare one project story and one reason for the role. The project story is five to eight minutes. Open on a constraint and the choice you made.
Practice focusRequirements - State why you chose that approach, what you turned down, and what you measured. - Lead with the technical choice, not a business result. - Be ready for a redirect to recent work, a deeper bottleneck, or an option you did not use. - The motivation names a real direction you can contribute to, tied to a skill you have already used. - Keep two depths ready: the system shape, and the kernel or model detail. Pick the depth the conversation asks for. - Keep a short reset so a redirect does not lose the thread. Review checklist 1.…
Reported interview periodNot available
Tell one story about a consequential decision you made with incomplete evidence. State what was known, what was unknown, the reversible step you chose, and the signal that would make you change course.
Practice focusPreparation - Write the user or stakeholder, the constraint, and the decision in one sentence each. - Choose one measurement or observable fact that can support the answer. - Name one alternative and the reason it was not selected. Review checklist 1. Did I state the concrete constraint before describing the solution? 2. Did I separate my own decision and work from the team's work? 3. Did I name evidence or a measurement rather than relying on confidence? 4. Can I answer every follow-up without changing the original facts? Staged follow-ups 1.…
Reported interview periodNot available
You own a useful model feature with a fixed launch date and one unresolved safety concern. Explain the concern, bound the plausible harm, choose what ships, and define the evidence required before expanding acc…
Practice focusPreparation - Write the user or stakeholder, the constraint, and the decision in one sentence each. - Choose one measurement or observable fact that can support the answer. - Name one alternative and the reason it was not selected. Review checklist 1. Did I state the concrete constraint before describing the solution? 2. Did I separate my own decision and work from the team's work? 3. Did I name evidence or a measurement rather than relying on confidence? 4. Can I answer every follow-up without changing the original facts? Staged follow-ups 1.…
Reported interview periodNot available
Walk through a system you made more reliable after a serious failure. Cover the failure boundary, your diagnosis, the design change you owned, the rollout, and the evidence that recovery improved.
Practice focusPreparation - Write the user or stakeholder, the constraint, and the decision in one sentence each. - Choose one measurement or observable fact that can support the answer. - Name one alternative and the reason it was not selected. Review checklist 1. Did I state the concrete constraint before describing the solution? 2. Did I separate my own decision and work from the team's work? 3. Did I name evidence or a measurement rather than relying on confidence? 4. Can I answer every follow-up without changing the original facts? Staged follow-ups 1.…
Reported interview periodNot available
Tell one story about a disagreement with a product, research, policy, or operations partner. State the shared goal, the competing constraints, what you changed in your own position, and the decision the group m…
Practice focusPreparation - Write the user or stakeholder, the constraint, and the decision in one sentence each. - Choose one measurement or observable fact that can support the answer. - Name one alternative and the reason it was not selected. Review checklist 1. Did I state the concrete constraint before describing the solution? 2. Did I separate my own decision and work from the team's work? 3. Did I name evidence or a measurement rather than relying on confidence? 4. Can I answer every follow-up without changing the original facts? Staged follow-ups 1.…
Reported interview periodNot available
A team can improve model quality, reduce latency, or make failures easier to understand, but can fund only one this quarter. Choose a direction, state the users and evidence behind it, and define what would inv…
Practice focusPreparation - Write the user or stakeholder, the constraint, and the decision in one sentence each. - Choose one measurement or observable fact that can support the answer. - Name one alternative and the reason it was not selected. Review checklist 1. Did I state the concrete constraint before describing the solution? 2. Did I separate my own decision and work from the team's work? 3. Did I name evidence or a measurement rather than relying on confidence? 4. Can I answer every follow-up without changing the original facts? Staged follow-ups 1.…
Reported interview periodNot available
Walk through a project where you reduced latency or cost without weakening correctness. Cover the baseline, bottleneck, alternatives, the change you owned, rollout safeguards, and measured result.
Practice focusPreparation - Write the user or stakeholder, the constraint, and the decision in one sentence each. - Choose one measurement or observable fact that can support the answer. - Name one alternative and the reason it was not selected. Review checklist 1. Did I state the concrete constraint before describing the solution? 2. Did I separate my own decision and work from the team's work? 3. Did I name evidence or a measurement rather than relying on confidence? 4. Can I answer every follow-up without changing the original facts? Staged follow-ups 1.…
Reported interview periodNot available
Explain why a high-ownership role fits you using one project where you found an unowned problem, chose a direction, and delivered a measurable result. State the boundary of your authority and when you asked for…
Practice focusPreparation - Write the user or stakeholder, the constraint, and the decision in one sentence each. - Choose one measurement or observable fact that can support the answer. - Name one alternative and the reason it was not selected. Review checklist 1. Did I state the concrete constraint before describing the solution? 2. Did I separate my own decision and work from the team's work? 3. Did I name evidence or a measurement rather than relying on confidence? 4. Can I answer every follow-up without changing the original facts? Staged follow-ups 1.…
Reported interview periodNot available
Walk through a project where scale exposed a bottleneck. Cover the workload, the measured limit, your model of the bottleneck, the intervention you owned, and the evidence that the limit moved.
Practice focusPreparation - Write the user or stakeholder, the constraint, and the decision in one sentence each. - Choose one measurement or observable fact that can support the answer. - Name one alternative and the reason it was not selected. Review checklist 1. Did I state the concrete constraint before describing the solution? 2. Did I separate my own decision and work from the team's work? 3. Did I name evidence or a measurement rather than relying on confidence? 4. Can I answer every follow-up without changing the original facts? Staged follow-ups 1.…
Reported interview periodNot available
Turn an unknown biased bit source into balanced choices, a sampled load estimate, and isolated concurrent batches.
Practice focusYou receive a hardware source raw bit() that independently returns 0 or 1 with one stable but unknown probability of returning 1 . The probability is strictly between zero and one, and no other random source is available. Implement the following four functions. Requirements 1. Extract balanced bits Read the raw source in fresh pairs. Discard pairs whose values match. For the first pair whose values differ, return its first value. A scripted source raises EOFError when exhausted; let that exception propagate, including for a partial pair.…
Reported interview periodNot available
Given a nondecreasing array and a target value, report where the target first appears, or -1 when it is missing. A logarithmic search is expected, even though the same value may occur many times.
Practice focusRequirements - Line one is the element count n . Line two holds the n space-separated integers in nondecreasing order, and is empty when n is 0. Line three is the target. - Return the smallest zero-based index holding the target, as a decimal string with no padding. - Return -1 when the array is empty or the target never appears. - Repeated values are expected, so an ordinary equality hit is not enough; after a match keep searching to the left while remembering the best index seen. - Keep the running time logarithmic in n .…
Reported interview periodNot available
A single thread records start and end events for nested function calls. For each function id, work out how many time units it actually spent running, excluding the units spent inside calls it made.
Practice focusRequirements - Line one is the number of functions; ids run from 0 to count - 1 and every id appears at least once. Line two is the number of event lines. - Each remaining line is <id :<start|end :<timestamp with integer fields. Events are chronological and properly nested on one thread. - An end timestamp is inclusive: the unit at that timestamp belongs to the call that is ending, so it contributes timestamp - previous + 1 units. - When a call begins on top of a running call, credit the units since the previous boundary to the caller.…
Reported interview periodNot available
Each house on a street holds a known amount of money, and robbing two neighboring houses on the same night trips the alarm. Choose houses with no two adjacent to collect the largest possible total.
Practice focusRequirements - Line one is the house count. Line two lists that many non-negative integer amounts, separated by spaces. - Adjacency is positional, so choosing the house at index i rules out only i - 1 and i + 1 . - Return the best total as a decimal string with no separators. - A single house contributes its own amount, and a zero amount is a legal choice, so a street of zeros answers 0 . - Every house is a candidate; skipping a house is never required just because it is small. - run case passes case["stdin"] to solve .…
Reported interview periodNot available
Two Python-style lists arrive as literal assignments. Collect every value that belongs to the first list but not the second, keeping the first list's order.
Practice focusRequirements - The input holds two assignment statements, one per entry: list1 = [...] followed by list2 = [...] . Both lists contain integers and may be empty. - The statements may be separated by a real newline or by a literal two-character \n escape; split on either form. - Return the kept values in their original list1 order. - Membership in list2 is decided by value, not by count or position, so a single occurrence there removes every matching occurrence in list1 .…
Reported interview periodNot available
Given a list of half-open time ranges, report the largest number of ranges that are active at the same instant.
Practice focusRequirements - Line 1 holds the number of bookings. Each following line holds start end , two integers with start strictly less than end . - Treat a booking as occupying the half-open interval [start, end) . - Because the interval is half-open, a booking that ends at a time does not conflict with one that starts at that same time. - Return the peak number of concurrent bookings as a decimal string. - An empty booking list returns "0" . - run case(case: dict) forwards case["stdin"] to solve .…
Reported interview periodNot available
Combine three nondecreasing integer lists into one nondecreasing list in which every distinct value appears once, then print it as a single space-separated line.
Practice focusRequirements - The input has exactly three lines. Each line starts with a count k followed by k nondecreasing integers. - The merged result must stay sorted and must contain each distinct value exactly once. - Values may be negative, zero, or positive. Duplicates can appear within one line and across lines. - Print the distinct values in one line separated by single spaces, with no leading or trailing space. - If all three lists are empty, return an empty string. - run case(case: dict) forwards case["stdin"] to solve .…
Reported interview periodNot available
Rearrange an integer list into the next larger lexicographic arrangement, wrapping around to the smallest arrangement when no larger one exists.
Practice focusRequirements - Line 1 holds the length n . Line 2 holds n integers separated by spaces. - Compare arrangements position by position from the left. The next arrangement is the smallest arrangement strictly greater than the current one. - Duplicate values are allowed. - If the current arrangement is already the largest, return the smallest arrangement, with values in ascending order. - Print the resulting list in one space-separated line, keeping the same length and the same multiset of values. - run case(case: dict) forwards case["stdin"] to solve .…
Reported interview periodNot available
Given a nondecreasing integer sequence, report how many different values it contains.
Practice focusRequirements - The input is one line of space-separated integers in nondecreasing order. - Equal values are therefore adjacent, and the sequence may contain negative values. - Return the number of distinct values as a decimal string. - You do not need to print or return the compacted sequence itself. - run case(case: dict) forwards case["stdin"] to solve . - Do not append a trailing newline to the returned string; return the value exactly once.