Interview questions

Implement MoE and show the dimensions

Companies: NVIDIA

Implement NumPy functions using C in less than 40 minutes. Other ones were just LC hards.

Companies: Databricks

Implement Queue using Stacks

Implement a FIFO queue using only stack operations (push, pop/peek, size/isEmpty) by composing two stacks to support push, pop, peek, and empty. Aim for an…

General practice

Implement Rand10() Using Rand7()

Implement rand10() using only the uniform rand7() API so that outputs 1..10 are equally likely; the core challenge is converting a size-7 uniform distribution into…

General practice

Implement Router

Design a Router that stores up to memoryLimit packets in FIFO order, rejects duplicates (same source, destination, timestamp), evicts the oldest packet when full, and…

General practice

Implement something like an order system.

Companies: Jane Street

Implement Stack using Queues

Implement a LIFO stack using only standard queue operations (push to back, pop/peek from front, size, isEmpty), supporting push, pop, top, and empty; the key…

General practice

Implement the frontend version of a traffic light

Companies: Roblox

Implement the game of minesweeper

Companies: Uber

Implement Trie II (Prefix Tree)

Design a prefix tree that supports insert, countWordsEqualTo, countWordsStartingWith, and erase operations, handling duplicate inserts/removals by maintaining node-level…

General practice

Increasing Decreasing String

Reorder a lowercase string by repeatedly building increasing then decreasing runs: repeatedly append the smallest unused character, then successive larger unused characters…

General practice

Increasing Order Search Tree

General practice

Increasing Triplet Subsequence

Check whether the array contains an increasing triplet subsequence (indices i<j<k with nums[i]<nums[j]<nums[k]). The challenge is to do it efficiently for n up to 5e5…

General practice

Increment Submatrices by One

Given n and a list of axis-aligned submatrix queries that add +1 to every element in each rectangular region, compute the final n×n matrix; the…

General practice

Incremental Even-Weighted Cycle Queries

General practice

Incremental Memory Leak

Simulate a greedy allocation where at second i you allocate i bits to the stick with more available memory (or the first if tied), and…

General practice

Index Pairs of a String

Given a string and a list of words, return all index pairs [i, j] where the substring text[i..j] matches any word from the list (overlapping…

General practice

Infinite Method Object

Design an object that allows calling any (unknown) method name repeatedly in a chain—each call returns the same object so chaining can continue indefinitely—and that…

General practice

Inorder Successor in BST

Given the root of a binary search tree and a target node p, return p's in-order successor — the node with the smallest key greater…

General practice

Inorder Successor in BST II

Given a node in a binary search tree where each node has left, right, and parent pointers (and you may not have the root), find…

General practice

Insert Greatest Common Divisors in Linked List

General practice