Tries

Given a string s and a dictionary of strings wordDict, return true if s can be segmented into a space-separated sequence of one or more dictionary words. The same dictionary word may be reused any number of times.

Design a WordDictionary supporting addWord(word) and search(word), where search may contain the wildcard . that matches any single letter. search returns true if at least one added word matches.

Design and implement a data structure that efficiently stores and retrieves words based on their prefixes, allowing for fast lookup and insertion operations.

Design an in-memory file system supporting four operations: ls(path) returns a file's name if path is a file, or a directory's child names in lexicographic order if it is a directory; mkdir(path) creates a directory, creating any missing intermediate directories; addContentToFile(filePath, content) creates the file if it does not exist and appends content; and readContentFromFile(filePath) returns the file's full content.