%!PS

% begin included library code
% see https://codeberg.org/Firedrake/postscript-libraries/
/test.start {
    print (:) print
    /test.pass 0 def
    /test.count 0 def
} 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

/apush.left { % [b c] a -> [a b c]
    exch % a [b c]
    [ 3 1 roll aload pop ]
} bind def

/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

/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

/lastvisitor {
    0 dict begin
    /a exch def
    [
        /seen 0 array def
        /minusones 0 def
        a {
            /n exch def
            n -1 eq {
                /minusones minusones 1 add def
                minusones seen length le {
                    seen minusones 1 sub get
                } {
                    -1
                } ifelse
            } {
                /seen seen n apush.left def
                /minusones 0 def
            } ifelse
        } forall
    ]
    end
} bind def

(lastvisitor) test.start
[5 -1 -1] lastvisitor [5 -1] deepeq test
[3 7 -1 -1 -1] lastvisitor [7 3 -1] deepeq test
[2 -1 4 -1 -1] lastvisitor [2 4 2] deepeq test
[10 20 -1 30 -1 -1] lastvisitor [20 30 20] deepeq test
[-1 -1 5 -1] lastvisitor [-1 -1 5] deepeq test
test.end