For every window of k consecutive elements, count how many distinct values it contains.

BackendGoogleMetaMicrosoft

Find the index where an array of positive integers splits into two contiguous parts with equal sums, or -1 if there isn't one.

BackendMeta

Merge two sorted arrays into one sorted array where every distinct value appears exactly once.

BackendMicrosoft

Filter articles by case-insensitive search across title and tags.

Group transactions by category and sum amounts.

Validate form fields using a data-driven rule array.

Build a centered letter pyramid.

Print a hollow square pattern.

Fix the classic closure bug where setTimeout callbacks all capture the same variable.

Fix broken inheritance and implement a new Human class

Find two indexes with sum equal to target

For every word, find the shortest prefix that no other word in the list starts with.

BackendMeta

Rank songs by how many other songs they beat head-to-head across users' preference lists, breaking ties by the smaller song id.

BackendExpedia

Cover every hole in a table with exactly two boards of the same integer length, and return the shortest length that works.

BackendMetaMicrosoft

Given [child, parent] pairs describing a forest, return the root of the tree with the most nodes, breaking ties by the smallest root ID.

BackendMicrosoftGoogleGoldman Sachs

Compute the greedy sequence of transfers that brings every account balance up to a threshold, or detect that it is impossible.

Retry an async operation with limits

Flatten a nested comment tree up to a depth limit, with metadata for indented rendering.

Implement a web crawler that discovers same-domain pages.

Build a button rate limiting the clicks