re: Sudoku

1) Not strict and warnings clean.
2) perl -c on 

     if( $puzmap[$bestpos] & 1 == 0 )

gives:

     "Possible precedence problem on bitwise & operator at
sudoku_ip.pl line ..."

but this seems to be a clash between undeclared variables.

The intended precedence seems to be 

    if( ( $puzmap[$bestpos] & 1 ) == 0 )

but this gives me:

    "Whoops - bestpos is a given square at..."

Changing the precedence to 

    if( $puzmap[$bestpos] & ( 1 == 0 )

seems to generate the right answer.

Is this what you intended?