Given a list of words and an integer k, return the k most frequent words in the list. The words should be sorted by their frequency in descending order. If two words have the same frequency, they should be sorted lexicographically.
Design a custom HashSet without using any built-in hash table libraries. Implement the MyHashSet class with methods to add, remove, and check the existence of a value.
Given an array of strings words, return the longest word in the list that can be built progressively one character at a time by other words in the list.
You are given a list of accounts, where each account consists of a name and a list of emails. Merge accounts that share common emails, and return the merged accounts in the format: name followed by sorted emails.
You are given an integer array nums. You want to maximize the number of points you can earn by performing the following operation any number of times: Pick any nums[i] and delete it to earn nums[i] points. Afterwards, you must delete every element equal to nums[i] - 1 and every element equal to nums[i] + 1.
You are given a lock with 4 rotating wheels, each containing 10 slots labeled ‘0’ to ‘9’. The wheels can rotate freely and wrap around. You must determine the minimum number of moves required to reach a target lock configuration, avoiding certain deadends.
