Fresh interview reports, verified and promoted into WhiteBox practice when signal is strong.
Problem statement You have 2^n players in a fixed single elimination tournament, labeled 0 to 2^n - 1. Round 1 is 0 vs 1, 2 vs 3, and so on. In later rounds, winners from neighboring bracket blocks play each other. Given p[i][j], the prob…
Result: got offer The loop had a few coding / ds rounds and one refactor / OOP-style round. Round 1: The interviewer asked me to design a data structure that supports: add(data, time) time is always given in increasing order. delete(…
given a m x n matrix with values in one operation: 1. you can select one row 2. remove either first element or last element from the row if you remove first element, then second element becomes the first we can perform these operations e…
Optiver runs a system that keeps track of all currently active orders for a given financial instrument. The orders must be maintained in sorted order by price. As new orders arrive and existing orders are removed, the system needs to suppor…
Implement a hash ring data structure, which is a consistent hashing ring that routes chat sessions to servers several levels: lvl 1: add/remove/get server lvl 2: virtual servers inside of a server lvl 3: server affinities, based on proximi…
Problem Statement you're in a city where cars uses special plat formats. The x-th license plate in a sequence that transitions through the following formats as each capacity is exhausted: 1. 00000 - 99999 2. A0000 - Z9999 3. AA000 - ZZ999 4…
koah labs interview 3 rounds r1 project / resume deep dive r2 45 min technical interview. tf-idf building like some basic search engine. input / output style, you're given definitions and can also look up stuff. can decide implementation…
Given a const int*, write a function and function call that causes printing the dereferenced pointer to print 42. example: given something like const int* x; you want to write a function such that f(...) and then after this function call,…
Interviewed for squarepoint swe in emea region was asked to implement vector class starting off with the push_back() function then other functions of similar complexity as an extension
Construct the optimal unbiased estimator for some random variable p', where p' is the probability that 5 i.i.d. RV p all fail together For each day, the probability of a machine failing is p. Estimate the probability p' of 5 of these machi…
I interviewed for a core AWS security team. The first interview was composed of a BFS/DFS proble. Even though the leetcode was easy, being a security team I was asked about stack overflow, memory management and how to parallelize it. The a…
path with minimum effort on leetcode i solve with dijkstra
Implement a rate limiter. First with easy constraints, then large constraints on the size of the blocks that can be passed in
Given a data stream, calculate the rolling correlation of the data stream. started out by doing the easy naive where you just add X, Y, XX and YY and then was told to optimize it to be numerically stable, where I would need Welford's algo…
What is the difference between function overloading and function overriding? Given some code, can you write some examples of both?
Given some example code for an ObjectPool, debug it and add some additional features.
Design tic-tac-toe, RLE iterator tic tac toe is just a simple state machine (messed up on some logic but it was fine) RLE iterator was easy, just expand upon construction and iterate like a normal array
maximize distance to closest person, literally check consecutive elements thats it also task scheduler, which was the heap question on leetcode where you want to interleave as many tasks as possible and keep n between tasks of the same id.…
Interviewed with Roblox, had a superday of 2 technical + 1 behavioral back-to-back. First interview was given an array of 0s and 1s, find the 1 that is furthest apart from any 0s/start/end. Second interview was given an array of integers, c…
I interviewed with Apple for a software engineering internship. There were 2 interviews, the second was coding and I got a LeetCode easy problem to check if a string is a palindrome, excluding spaces and special characters. I could choose a…
Question: In quantum error correction, what do logical operators act on? A) The physical refrigerator B) The classical optimizer only C) The encoded logical information without leaving the code space D) The number of shots in the experimen…
Question: What is a key feature of CSS quantum error-correcting codes? A) They require only one physical qubit per logical qubit B) They separate bit-flip and phase-flip error checks using structures derived from classical linear codes C)…
Question: In stabilizer quantum error correction, what does the syndrome measurement reveal? A) The exact unknown quantum state B) A perfect copy of the logical qubit C) The final answer of the quantum algorithm D) Information about which…
Question: What is a major practical cost of Probabilistic Error Cancellation? A) It can require large sampling overhead because noisy operations are represented using quasi-probability decompositions B) It prevents expectation values from…
Question: What is the purpose of dynamical decoupling in quantum execution? A) To make CNOT gates irreversible B) To convert quantum outputs into SQL rows C) To insert pulse or gate sequences that help suppress idle-qubit decoherence D) To…
You are trying to optimize generating a simulation of autocorrelated coin flips with p = 0.7. The baseline is simply iterating over each element, using random generation with the previous element's value. Can we do better? Hints: think XO…
Question: What is the main idea behind Zero-Noise Extrapolation? A) Remove all physical qubits from the circuit B) Run circuits at different effective noise levels and extrapolate toward the zero-noise limit C) Replace quantum gates with c…
Question: In VQE or Hamiltonian expectation estimation, why are Pauli terms often grouped before measurement? A) To make all Hamiltonians diagonal in the computational basis B) To avoid using ansatz circuits C) To remove the need for class…
Question: What is the Sampler primitive mainly designed to return? A) Samples or probability-like distributions over measured bitstrings B) Ground-state energies only C) Hamiltonian matrix decompositions only D) Coupling-map diagrams only…
Question: In Qiskit-style workflows, what is the Estimator primitive mainly used to compute? A) Raw bitstring counts only B) The shortest path in the coupling map C) Expectation values of observables for quantum circuits D) The number of q…