The file 'sudoku.tgz' contains a selection of programs and files 
related to the solution of Sudoku puzzles by straightforwars DFS algorithms.

Note.  Programs and files related to other studies like
       - statistical analysis of execution times and number of visits,
       - discrimination (partition) of a set of puzzles by 
         invariant properties,
       are not included.]

 --- For unix-like systems (linux, OS Xcode,...) ---

1)    Uncompress the file sudoku.tgz
        $ tar -xvzf sudoku.tgz
        $ cd pub   
      Note: "pub" is the directory just created.

2)    Make 'doall' executable
        $ chmod +x doall

3)    Make 'do-long-file' executable
        $ chmod +x do-long-file

4)    Solve puzzles "ex-A",..., "ex-E"
        $ ./doall
      Note: "doall" includes various compilations 
            "gcc -O3 suall.c". One would be enough...
      Note: if you want to run a single test, you can do, for instance
        $ gcc -O3 suall.c
        $ a.out < ex-B

5)    Solve all 49151 puzzles.
        $ ./do-long-file
      Note. I used the file prepared by Gordon Royle 
            of the University of Western Australia.

6)    Note. The input file format is quite flexible. Look to the code

      int nextd(void){
        int c;
        while(c!='-' & (c<'0' || c>'9'));
        return c-'0';

      void readm(void){
        int i,j;