%!PS

% begin included library code
% see https://github.com/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

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

/goodpairs {
    1 dict begin
    /k 0 dict def
    {
        dup k exch known {
            dup k exch get
        } {
            0
        } ifelse
        k 3 1 roll 1 add put
    } forall
    0
    k values {
        dup 1 sub mul add
    } forall
    2 idiv
    end
} bind def

(goodpairs) test.start
[1 2 3 1 1 3] goodpairs 4 eq test
[1 2 3] goodpairs 0 eq test
[1 1 1 1] goodpairs 6 eq test
test.end