(define (rename t)
  (define (rename-st t i)
    (let ([value (car ((rand1 1000000) i))]
          [seed (cdr ((rand1 1000000) i))])
      (cond [(leaf? t) (res value seed)]
            [(node? t)
             (let* ([rl (rename-st (node-left t) seed)]
                    [rr (rename-st (node-right t) (res-state rl))])
               (res (node (res-val rl) (res-val rr))
                    (res-state rr)))])))
  (res-val (rename-st t 0)))

(define (rename2 t)
  (define (rename-st t)
    (cond [(leaf? t)
           (rand1 340)]
          [(node? t)
           (st-app node
                   (rename-st (node-left  t))
                   (rename-st (node-right t)))]))

  (res-val ((rename-st t) 0)))