%!PS

% begin included library code
% see https://codeberg.org/Firedrake/postscript-libraries/
/keys { % dict -> array of dict keys
    [ 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

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

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


% end included library code

/uniquenumber {
    0 dict begin
    /c 0 dict def
    {
        /n exch def
        c n c n 0 dget 1 add put
    } forall
    -1
    c keys {
        /n exch def
        c n 0 dget 1 eq {
            pop n
            exit
        } if
    } forall
    end
} bind def

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