%!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

/keys { % dict -> array of dict keys
    [ 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

/jumpgame {
    0 dict begin
    /a exch def
    /target a length 1 sub def
    /here << 0 true >> def
    /moves 0 def
    {
        /moves moves 1 add def
        /there 0 dict def
        here keys {
            /n exch def
            n 1 add 1 n a n get add target min {
                there exch true put
            } for
        } forall
        there length 0 eq {
            -1
            exit
        } if
        there target known {
            moves
            exit
        } if
        /here there def
    } loop
    end
} bind def

(jumpgame) test.start
[2 3 1 1 4] jumpgame 2 eq test
[2 3 0 4] jumpgame 2 eq test
[2 0 0 4] jumpgame -1 eq test
test.end