Two Sigma Interview Questions

You're given an array representing weights. Implement a function to randomly pick an index from the array, where the probability of picking each index is proportional to its weight.

Imagine a map where cities are connected by roads. Given a list of roads, find how many separate groups of connected cities (provinces) there are.

Find the minimum number of operations to reduce a given positive integer to 0. You can either subtract a power of 2 or add a power of 2 in each operation.

Find the largest possible sum of a contiguous subarray after deleting at most one element from the original array. You need to consider the cases with no deletion and with one deletion.

Determine if a given integer is a power of four. That is, can the number be expressed as 4 raised to some integer power?

Simulate multiplication of two non-negative integers represented as strings. Return the product, also represented as a string.

Find the maximum possible sum of a non-empty subarray within a circular array. The circular array means the end connects to the beginning.

Determine if a string matches a pattern containing wildcard characters '?' (matches any single character) and '*' (matches any sequence of characters, including the empty sequence).

Find the common elements present in two given arrays. Return an array containing these intersecting elements, ensuring each element appears only once.

Simulate the Game of Life, updating the state of a board based on the rules of cell survival and death in each generation. Modify the board in place to represent the next generation.

You are given a list of words. Find the longest possible chain of words where each word is formed by adding exactly one letter to its predecessor.

You are given a board of characters and a list of words. Find all the words from the list that can be formed by traversing adjacent cells on the board.

You are given k sorted lists. Combine all of their elements into a single sorted list and return it.

Simulate a basic memory allocator. You'll need to allocate blocks of memory, track their IDs, and free them based on their ID.

You're given courses with prerequisites and time to complete each. Find the minimum time to finish all courses, taking dependencies and parallel study into account.

You're given boxes of products and suppliers offering packages of various sizes. Find the minimum wasted space when fitting all the products into one supplier's package.

Implement a hash map data structure from scratch. You need to handle basic operations like insertion, retrieval, and deletion of key-value pairs.

Implement a Tic-Tac-Toe game where players take turns placing their marks. Design the game logic to efficiently determine the winner after each move.

You are given a list of meeting time intervals. Determine the minimum number of conference rooms required to accommodate all the meetings without any overlap.

Implement a search suggestion system. Given a search word and a list of product names, return the top 3 product suggestions after each character of the search word is typed.