solutions-use-no-external-dependencies

Status: IN

Solution files use only Python builtins and standard library modules (e.g., `unittest`, `typing`); no third-party packages are imported.

Source: entries/2026/06/06/1-bit-and-2-bit-characters-solution.md, entries/2026/06/06/add-digits-solution.md, entries/2026/06/06/add-strings-solution.md, entries/2026/06/06/add-to-array-form-of-integer-solution.md