%!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

/listmax {
    { max } reduce
} bind def

/reduce { % array proc -> value
    2 dict begin
    /p exch def
    /a exch def
    a 0 get
    1 1 a length 1 sub {
        a exch get
        p
    } for
    end
} bind def

/filter { % array proc(bool) -> array
    1 dict begin
    /p exch def
    [ exch
      {
          dup p not
          {
              pop
          } if
      } forall
    ]
    end
} bind def

/dget {
    3 1 roll
    2 copy
    known {
        get exch pop
    } {
        pop pop
    } ifelse
} bind def

/values { % dict -> array of dict values
    [ exch
      {
          exch pop
      } forall
    ]
} 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

/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


% end included library code

/maximumfrequency {
    0 dict begin
    /c 0 dict def
    {
        c exch
        2 copy
        0 dget 1 add put
    } forall
    /mx c values listmax def
    c values { mx eq } filter length mx mul
    end
} bind def

(maximumfrequency) test.start
[1 2 2 4 1 5] maximumfrequency 4 eq test
[1 2 3 4 5] maximumfrequency 5 eq test
test.end