🔢 FastSudoku

This repository contains a super efficient implementation of a Sudoku solving algorithm capable of handling any valid 9x9 Sudoku puzzle.

The latest version can solve almost any board in under 9 microseconds (μs) — that’s under 9 millionths of a second!

The algorithm uses techniques like Minimum Remaining Values (MRV) Backtracking to accelerate the solving process.

💨 LeetCode Performance

solution can be found here and another one here

note that the variance of the times is massive, their testing VM is shit

• 0 ms runtime — beats 100% of C++ submissions ⏱️
• 29.51% better than other solutions in memory usage 🧠

🔥 IMPORTANT DISCLOSURE 🔥

All benchmark results were obtained under controlled conditions using the selected board (#x) for the 10k test, and a fixed batch of 12 test cases for cumulative timing — similar in style to how LeetCode benchmarks.

⚠️ All binaries were compiled using the -Ofast optimization flag.

TESTED ON:

• Linux macbook-air 6.13.7-arch1-1 #1 SMP
• PREEMPT_DYNAMIC Thu, 7 Apr 2025
• 11:34:00 +0000 x86_64 GNU/Linux

⚡ Benchmark Results (Latest Version)

Test Case	Time (ms)	Time (μs)	Time (ns)
Board #7 (10k average)	0	7	8,218
12-board cumulative test	6	6,243	6,243,730
Hardest board (#6)	1	1,919	1,920,297
Second hardest board (#2)	1	1,728	1,729,112
Third hardest board (#10)	1	1,716	1,717,267
Empty board	0	9	10,227
Single-cell board	0	8	8,981
Three-cell board	0	7	8,031
Five-cell board	0	7	7,789

📥 Download, Compile & Run It Yourself

Clone the repository:

git clone https://github.com/theargcoder/FastSudoku/
cd FastSudoku

OPTIONAL

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Edit the following in board_solver/main.cpp

• test_individual, test_n_times, and test_commulative functions – modify these to suit your test style.

• boards_gpt– update this vector to try out your own boards.

• You can also uncomment previous versions of the solver to benchmark them too!

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Compile inside board_solver/ with:

For some compiler optimization

 g++ -std=c++17 -Wall -O2 main.cpp -o main

For a lot of compiler optimization

 g++ -std=c++17 -Wall -O3 main.cpp -o main

For THE MOST compiler optimization possible

 g++ -std=c++17 -Wall -Ofast main.cpp -o main

THANKS

Enjoy the speed. 🧠💨