OA — Cloud File-Storage System (4 Levels)

A CodeSignal four-level OA modeling an in-memory cloud storage system: add/copy/get files, prefix/suffix search, per-user capacity limits, and file compression/decompression. Requirements Implement an in-memory cloud storage system mapping files to metadata (name, size). Four progressive levels; any solution passing the unit tests is accepted. Level 1 — Core file ops (signatures as given in the prompt): bool AddFile(const std::string& name, int size); // Adds file `name` of `size` bytes. Fails (returns false) if a file with that name already exists. bool CopyFile(const std::string& name_from, const std::string& name_to); // Copies name_from -> name_to. Fails if name_from doesn't exist or is a directory, // or if name_to already exists. std::optional<int> GetFileSize(const std::string& name); // Returns the file's size, or nullopt if it doesn't exist. Level 2 — Search. Find files by matching prefixes and suffixes. Level 3 — Users & capacity. Add users each with their own capacity limit; account file sizes against the owning user's quota. Level 4 — Compression. Support compressing and decompressing files. It is guaranteed queries never create collisions between file and directory names. Examples AddFile("/dir1/dir2/file.txt", 10) -> true; adds file of 10 bytes CopyFile("/not-existing.file", "/dir1/file.txt") -> false; source does not exist CopyFile("/dir1/dir2/file.txt", "/dir1/file.txt") -> true AddFile("/dir1/file.txt", 15) -> false; file already exists CopyFile("/dir1/file.txt", "/dir1/dir2/file.txt") -> false; destination exists GetFileSize("/dir1/file.txt") -> 10 GetFileSize("/not-existing.file") -> nullopt Execution time limit 30s; memory limit 4g. Notes The signatures above are shown in C++ in the prompt, but the framework lets you implement in your language of choice; keep the same return semantics (false/nullopt on failure). Treat names as path-like strings; Level 2's prefix/suffix search and Level 3's per-user quota both read cleanly if Level 1 stores (name -> size, owner) rather than just (name -> size). Preparation Implement Levels 1–2 (add/copy/get + prefix/suffix search) and test the failure paths (duplicate add, copy of a missing/dir source, copy onto an existing name). Add per-user capacity accounting and a compress/decompress pair, keeping ownership and compressed-size bookkeeping consistent.