Heaps

Given an array of points where points[i] = [xi, yi] (2D Euclidean), and an integer k, return the k points closest to the origin (0, 0) (any order). Solve with a max-heap of size k — the canonical heap-based interview answer.

Given a string s, sort it in decreasing order based on the frequency of the characters (most frequent first). The frequency of a character is the number of times it appears in the string. Return the sorted string. If two characters have the same frequency, any valid ordering between them is accepted.

Given an integer array nums and an integer k, return the k-th largest element in the array. Note that it is the k-th largest in sorted order, not the k-th distinct element. Solve it using a min-heap of size k — the canonical heap-based interview answer.

Given an array of products and a string searchWord, design a system that, after each character of searchWord is typed, returns up to three product names that start with the prefix typed so far. When more than three products share the prefix, return the three lexicographically smallest. Return a list of lists — one suggestion list per typed character.