Sudoku

Sudoku by Likhith Praveen K is a clean, open-source 9×9 Sudoku game built with Flutter. It generates puzzles on the phone, saves an unfinished board for each difficulty and keeps completion records locally. There are no accounts, advertisements, purchases or online competition in this version.

This page covers F-Droid’s 1.2.0 64-bit ARM build, version code 72. We matched it to F-Droid’s signed index, inspected the Android manifest and read the fixed 1.2.0 generator, solver and interface source. We did not play a full puzzle or independently prove every generated board.

Four difficulties based on solving logic

The four choices are Easy, Medium, Hard and Expert. The generator first makes a complete grid, removes values while preserving a unique solution, and then asks the built-in logical solver to grade the result. Easy boards can be completed with basic techniques; higher levels introduce pairs, triples, box-line interactions and patterns including X-Wing and Swordfish. Expert also includes more advanced techniques.

The source uses target clue counts of 36, 30, 24 and 20 during generation and checks the techniques its own solver can apply. Easy through Hard are accepted by their technique bands without a separate brute-force solvability check. Expert can also accept a unique board that the logical solver does not finish and therefore needs trial and error. The labels are more than clue counts, but they are the app’s own grading rules rather than a promise that every board has a fully logical path.

Notes, validation and importing a board

During a game you can enter pencil marks, fill current candidate notes, undo moves and highlight other cells containing the selected digit. The source has an unused conflict-check helper, but version 1.2.0 does not call it to highlight rule conflicts. Validate compares entries with the stored solution, while a hint fills the first empty or incorrect cell in row order rather than choosing a teaching step.

The import dialog accepts an 81-character puzzle. Empty cells can be represented by 0, ., x, X or _. The app checks the grid, verifies that it has one solution and calculates a difficulty from the techniques its solver uses before opening it. Importing replaces any unfinished saved board at the calculated difficulty. This is text import, not a camera scanner or a cloud puzzle catalogue.

The current game is saved separately by difficulty, so you can leave an Easy board and return to it without replacing the in-progress Hard board. Finishing a puzzle writes a local record with the time, difficulty and whether assistance was used. The solved overlay and Statistics screen keep the fastest ten assisted and ten unassisted records separately for each difficulty.

Themes, layouts and offline privacy

The interface offers several named colour themes, but each has a fixed light or dark brightness; version 1.2.0 has no “follow system” mode. Its layout switches between portrait and landscape arrangements based on orientation, not screen width.

The measured APK declares only Android’s automatically generated signature permission for an internal dynamic receiver. It has no internet permission, and our scan found no known tracker SDKs. Puzzles, settings and statistics use local Hive databases. There is no account, cloud save or automatic sync; uninstalling the app can remove that data unless Android’s own backup system restores it.

F-Droid publishes architecture-specific variants. This download is the arm64-v8a build commonly used by current phones. The repository also has 32-bit ARM and 64-bit x86 files, but no 32-bit x86 build. A device with another supported architecture needs its matching variant rather than this APK, even though the game has the same version name.

About this file

• This is 1.2.0 for 64-bit ARM, version code 72, indexed by F-Droid and signed with the developer certificate recorded there.
• The 18.8 MB APK needs Android 7.0 or later. It contains arm64-v8a native libraries; other CPU variants are separate files.
• Its measured SHA-256 is 9acb68c5b541d6972a269a13a3c01d38fcd5ef174cf8de58e9952be67e35a60d, matching the selected entry in F-Droid’s signed index.
• It has no internet permission and our static scan found no known tracker SDKs.
• Sudoku is licensed under GPL-3.0-or-later.

CPU types in this build: arm64-v8a (64-bit ARM, almost every phone since 2017).

Versions currently kept in the F-Droid repository. We host and check only the newest one. Full changelog.