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.
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 string s and an array of strings words. Your task is to determine how many words from the array are subsequences of the string s. A subsequence of a string is derived by deleting some or no characters from the original string without altering the order of the remaining characters.
Given an array of words, you are to return the length of the shortest reference string that can encode these words. The reference string consists of the words concatenated with a ‘#’ character at the end, and indices are used to encode the words by identifying their position in the reference string. Each word is encoded by the substring in the reference string that starts at its position and ends at the next ‘#’.
