Hudson River Trading Online Assessment Questions

What to expect from HRT SWE OA?

Just received the Hudson River Trading OA for their SWE intern role, by their description it is not the standard GCA through CodeSignal since it is only three questions and 2 hours long. Anyone have a

[Help] Hudson River Trading C++ Online Assessment Tips?

Hey everyone! I recently received an invitation to complete an online assessment for a C++ Software Engineer role at Hudson River Trading, and I’m excited (and a bit nervous) about what to expect. The

Anyone done the HRT online assessment for 2023?

I'm applying for the Algo dev role (London) and trying to prepare. Apparently 90 mins to solve 3 hard leetcodes and 1 pandas question, yikes Anyone remember what questions came up?

Chemical Reaction Simulation: Model Chain Reactions and Find Stable End States

## Problem You are given a list of chemical reaction rules: `A + B -> C` means combining elements A and B produces C. Given an initial set of elements, simulate the reactions until no more reactions are possible, then return the final stable set. Reactions trigger in any order when the required elements are both present. An element is consumed when it participates in a reaction. ```python def simulate_reactions( initial: list[str], rules: list[tuple[str, str, str]] # (reactant1, reactant2, product) ) -> list[str]: ... ``` ``` rules: [("H","O","W"), ("W","C","X"), ("H","N","Y")] initial: ["H", "H", "O", "C", "N"] Step 1: H+O -> W remaining: [H, C, N, W] Step 2: W+C -> X remaining: [H, N, X] Step 3: H+N -> Y remaining: [X, Y] No more rules apply. Output: ["X", "Y"] ``` ## Follow-ups 1. The order of reactions can affect the final state (some reactions compete for the same element). How would you detect and report all possible stable end states? 2. What data structure lets you efficiently find which rules are currently triggered given the current element multiset? 3. How do you detect infinite loops (A+B->A+B is a degenerate rule)? 4. Extend to support catalytic reactions where element C is consumed then reproduced (e.g. C remains after A+B+C->D+C).

Hudson River Trading SWE OA - Comment-Free Code Length

## Problem Given source code as a string, compute its length after stripping all comments (single-line and block comments). Involves careful string parsing and state tracking. ## Likely LeetCode equivalent No direct match. ## Tags strings, parsing, coding, oa

Ways to Make Palindrome: Count Minimum Insertions to Make a String a Palindrome

## Problem Given a string `s`, find the minimum number of characters to insert (at any positions) to make `s` a palindrome. Also return the count of distinct palindromes that can be formed with exactly that many insertions. ```python def min_insertions_palindrome(s: str) -> tuple[int, int]: """Returns (min_insertions, count_of_distinct_palindromes).""" ... ``` ``` Input: s = "ab" Min insertions: 1 (insert 'a' at end -> "aba", or insert 'b' at start -> "bab") Distinct palindromes: 2 Output: (1, 2) Input: s = "aab" Min insertions: 1 ("aaba" then? No... insert 'a' at end -> "aaba" not palindrome) Correct: insert 'b' before first 'a' -> "baab" YES, or insert 'a' -> "aabaa" YES Output: (1, 2) ``` ## Follow-ups 1. The minimum insertions equal `n - LPS(s)` where LPS is the Longest Palindromic Subsequence length. Prove this. 2. How do you count distinct palindromes? Walk through your approach, handling duplicate characters carefully. 3. What is the time and space complexity of the LPS DP? Can you optimize space from O(n^2) to O(n)? 4. Extend: what is the minimum number of deletions (not insertions) to make `s` a palindrome?