Hudson River Trading Software Engineer Phone Screen Questions
4+ questions from real Hudson River Trading Software Engineer Phone Screen rounds, reported by candidates who interviewed there.
What does the Hudson River Trading Phone Screen round test?
The Hudson River Trading phone screen typically lasts 45-60 minutes and evaluates core Software Engineer fundamentals. Candidates should expect 1-2 algorithmic problems, basic system design discussion at senior levels, and questions about relevant experience. The goal is to confirm technical competence before bringing candidates onsite.
Top Topics in This Round
Hudson River Trading Software Engineer Phone Screen Questions
I recently had an interview for a C++ new grad position at HRT. The interview lasted 30 minutes; we introduced ourselves and then it quickly began. The question was: Design a game. The board has 9x9 d
## Problem Simulate an auction or order book exchange: match buy/sell orders by price-time priority. Likely involves heaps or sorted structures for order matching. ## Likely LeetCode equivalent No direct match. ## Tags coding, heap, simulation, trading
## Problem Given an integer `n` and a list of integers `factors`, find the smallest integer strictly greater than `n` that is divisible by every element in `factors`. ```python def smallest_divisible(n: int, factors: list[int]) -> int: ... ``` ``` Input: n=10, factors=[3, 4] LCM(3,4) = 12 Smallest multiple of 12 > 10 -> 12 Output: 12 Input: n=12, factors=[3, 4] Must be STRICTLY greater than 12 -> 24 Output: 24 Input: n=0, factors=[5, 7] LCM=35, first multiple > 0 -> 35 Output: 35 ``` ## Follow-ups 1. How do you compute the LCM of a list of numbers? Walk through the GCD-based approach. 2. What is the time complexity of your solution and what are the edge cases (e.g., factors contains 1, or factors contains duplicates)? 3. What if `n` can be up to 10^18? Does your integer arithmetic still work in Python? In Java/C++? 4. Generalize: find the K-th integer greater than N divisible by all factors. How does the formula change?
Line Game: Optimal Strategy for a Positional Token-Moving Game on a Number Line
## Problem Two players alternate turns. There is a token on integer position `pos` on a number line. Each turn the current player moves the token left or right by any value in a given set `moves` (e.g., `{1, 3}`). A player who moves the token to position 0 wins. A player who cannot move (or is forced to move off the line) loses. Given `pos` and `moves`, determine if the first player wins with optimal play. ```python def first_player_wins(pos: int, moves: set[int]) -> bool: ... ``` ``` moves = {1, 3}, pos = 4 Winning positions (W) vs losing positions (L): pos=0: W (you just won) pos=1: W (move 1 -> 0) pos=2: L (can go to 1 or ... 1 is W for opponent; -1 invalid) pos=3: W (move 3 -> 0) pos=4: L (move 1->3 W for opp, move 3->1 W for opp) Output: False (first player loses) ``` ## Follow-ups 1. This is a combinatorial game theory problem. Describe the DP recurrence for `is_winning(pos)`. 2. What is the time complexity of your DP solution, and what is the memoization base case? 3. How does the problem change if moves can also increase `pos` (bidirectional movement)? 4. Extend to a 2D grid: the token is at `(r,c)`, allowed moves are `{up, down, left, right}`. The player who reaches `(0,0)` wins. How do you adapt your solution?
What to Expect in the Hudson River Trading Phone Screen Round
The Hudson River Trading Software Engineer Phone Screen round has a specific calibration purpose distinct from other rounds in the loop. Across 4+ verified reports on LeakCode for this exact round type, the consistent expectations: clear scoping of the problem before diving into a solution, explicit reasoning about complexity, structured handling of edge cases, and the ability to discuss trade-offs between two reasonable approaches.
Reports tagged with the Phone Screen round at Hudson River Trading show recurring patterns in difficulty and topic distribution. The Phone Screen round is typically 45-60 minutes; the interviewer is calibrated against a specific rubric. The discriminator between candidates who advance and candidates who do not is rarely the final correctness of the answer. It is the path: did you clarify, did you verbalize your approach, did you handle edge cases, and did you communicate throughout.
How To Prepare for This Specific Round
Filter the questions below to the most recent reports (past 6-12 months). Questions tagged for this exact round type from this exact company at this exact role level are the highest-signal data available. Older reports may reference questions that have since rotated out of the company's pool.
Practice 4-6 representative problems from this set under timed conditions. The goal is not memorization (companies rotate questions); the goal is to internalize the patterns the interviewer typically reaches for and the depth of follow-up to expect. Reports on LeakCode also tag the typical follow-up depth at this round type, which is the discriminating signal between hire and no-hire calibration.
Phone Screen Round Timing and Format
The Phone Screen round at Hudson River Trading typically runs 45-60 minutes. Use the first 2-3 minutes to clarify requirements; you should never start coding or designing without verifying the input/output format, constraints, and edge cases out loud. Use the next 5-7 minutes to verbalize your approach before writing any code. The middle 20-30 minutes are implementation. Reserve the final 10 minutes for testing with concrete examples and discussing optimization or trade-offs.
Time budget discipline is one of the most reliable senior-vs-junior discriminators in this round. Strong candidates verbalize where they are in their budget out loud ("I've used about 20 minutes, I have 15 minutes left for testing and one optimization"). This signals engineering maturity to the interviewer and creates positive feedback they can capture in writing.
Common Failure Modes in This Round
Reports tagged "no hire" at Hudson River Trading Software Engineer Phone Screen commonly cite: coding silently without verbalizing approach, jumping to implementation before clarifying requirements, missing edge cases (empty input, single element, very large input), producing working code that the candidate cannot refactor when asked, and failing to test their solution with concrete examples before declaring done.
The single most predictive failure mode in 2025-2026 reports: not asking clarifying questions. Interviewers at all FAANG companies are explicitly trained to weight this dimension. Strong candidates ask 3-5 clarifying questions even on problems that look obvious; weak candidates dive into code immediately. The clarifying-question check is often the first signal recorded in the interviewer's notes.
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