You can find an alternative list of top 10 hardest Sudoku puzzles here (with C source code to find them): https://github.com/hpenedones/sudoku https://github.c

You can find an alternative list of top 10 hardest Sudoku puzzles here (with C source code to find them): https://github.com/hpenedones/sudoku https://github.com/hpenedones/sudoku Basically, I have a solver and I count the number of backtracking decisions that the solver has to make.