This is a modest proof of concept where I intended to play with advanced human heuristics, and also with C++20, C++23 stdex::mdspan and stdex::mdarray, Modern CMake, Doctest BDD macros... Hence this overdesigned solution.

In the end, brute force solving is extremely fast: we don't really need heuristics like hidden singles, naked pairs/triples, pointing...

Yet the internals has been designed with these evolutions in mind. Hence the internal (optimized) bitset to model candidates in cells.

Many things remain to be done like

• cleaning dead code
• documenting some classes and design choices
• simplify the cells
• implement these human solving heuristics (see http://www.sudokusnake.com/techniques.php, http://angusj.com/sudoku/hints.php, etc)

The input format should be compatible with the puzzles available on Simple Sudoku website.

To compile the code you'll need

• a C++20 compiler like clang++ 13 for instance
• CMake 3.19

Then, the compilation can be done with:

# Configure in ../build/build-static-13
CXX=clang++ cmake -G Ninja -S . -B ../build/build-static-13 -DBUILD_SHARED_LIBS=NO  -DCMAKE_BUILD_TYPE=Release  -DCMAKE_CXX_FLAGS='-stdlib=libc++ -Wall -Wextra' -DCMAKE_EXE_LINKER_FLAGS='-stdlib=libc++' -DCMAKE_EXPORT_COMPILE_COMMANDS=On

# Compile
cmake --build ../build/build-static-13

Tests can be ran with

cd ../build/build-static-13 && ctest

# Or
../build/build-static-13/tests/tests

Copyright 2021, Luc Hermitte

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.