%!PS

% begin included library code
% see https://codeberg.org/Firedrake/postscript-libraries/
/test {
    /test.count test.count 1 add def
    {
        /test.pass test.pass 1 add def
    } {
        ( ) print
        test.count (....) cvs print
        (-fail) print
    } ifelse
} bind def

/apush.right { % [a b] c -> [a b c]
    exch
    [ exch aload length 2 add -1 roll ]
} bind def

/test.end {
    ( ) print
    test.count 0 gt {
        (Passed ) print
        test.pass (...) cvs print
        (/) print
        test.count (...) cvs print
        ( \() print
        test.pass 100 mul test.count idiv (...) cvs print
        (%\)) print
        (\r\n) print
    } if
} bind def

/apop.left { % [a b c] -> [b c] a
    dup 0 get exch
    [ exch aload length -1 roll pop ] exch
} bind def

/test.start {
    print (:) print
    /test.pass 0 def
    /test.count 0 def
} bind def

/keys { % dict -> array of dict keys
    [ exch
      {
          pop
      } forall
    ]
} bind def


/set.difference {
    4 dict begin
    /s 0 dict def
    /b exch def
    /a exch def
    a keys {
        /k exch def
        b k known not {
            s k true put
        } if
    } forall
    s
    end
} bind def

/deepeq {
    2 dict begin
    /a exch def
    /b exch def
    a type b type eq {
        a type /dicttype eq {
            a length b length eq {
                <<
                    a {
                        pop
                        true
                    } forall
                    b {
                        pop
                        true
                    } forall
                >>
                true exch
                {
                    pop
                    dup a exch known {
                        dup b exch known {
                            dup a exch get exch b exch get deepeq not {
                                pop false
                            } if
                        } {
                            false
                        } ifelse
                    } {
                        false
                    } ifelse
                } forall
            } {
                false
            } ifelse
        } {
            a type dup /arraytype eq exch /stringtype eq or {
                a length b length eq {
                    true
                    0 1 a length 1 sub {
                        dup a exch get exch b exch get deepeq not {
                            pop false
                            exit
                        } if
                    } for
                } {
                    false
                } ifelse
            } {
                a b eq
            } ifelse
        } ifelse
    } {
        false
    } ifelse
    end
} bind def


% end included library code

/encode {
    aload pop
    exch 1000000 mul add
} bind def

/decode {
    dup 1000000 idiv
    exch
    1000000 mod
    2 array astore
} bind def

/contiguousblock {
    0 dict begin
    /a exch def
    /y a length def
    /x a 0 get length def
    /starts 0 dict def
    0 1 x 1 sub {
        /cx exch def
        0 1 y 1 sub {
            cx exch
            2 array astore
            encode
            starts exch true put
        } for
    } for
    /maxblock 0 def
    {
        starts length 0 le {
            exit
        } if
        /start starts keys 0 get def
        /cstart start decode def
        /queue [ start ] def
        /visited << start true >> def
        {
            queue length 0 le {
                exit
            } if
            queue apop.left /here exch def /queue exch def
            /chere here decode def
            [
                [ -1 0 ]
                [ 1 0 ]
                [ 0 -1 ]
                [ 0 1 ]
            ] {
                /delta exch def
                delta 0 get 0 ge chere 0 get 0 gt or
                delta 0 get 0 le chere 0 get x 1 sub lt or and
                delta 1 get 0 ge chere 1 get 0 gt or and
                delta 1 get 0 le chere 1 get y 1 sub lt or and {
                    /cthere [
                        chere 0 get delta 0 get add
                        chere 1 get delta 1 get add
                    ] def
                    /there cthere encode def
                    visited there known not
                    a cthere 1 get get cthere 0 get get
                    a cstart 1 get get cstart 0 get get deepeq and {
                        visited there true put
                        /queue queue there apush.right def
                    } if
                } if
            } forall
        } loop
        /sz visited keys length def
        sz maxblock gt {
            /maxblock sz def
        } if
        /starts starts visited set.difference def
    } loop
    maxblock
    end
} bind def

(contiguousblock) test.start
[[(x) (x) (x) (x) (o)] [(x) (o) (o) (o) (o)] [(x) (o) (o) (o) (o)] [(x) (x) (x) (o) (o)]] contiguousblock 11 eq test
[[(x) (x) (x) (x) (x)] [(x) (o) (o) (o) (o)] [(x) (x) (x) (x) (o)] [(x) (o) (o) (o) (o)]] contiguousblock 11 eq test
[[(x) (x) (x) (o) (o)] [(o) (o) (o) (x) (x)] [(o) (x) (x) (o) (o)] [(o) (o) (o) (x) (x)]] contiguousblock 7 eq test
test.end