(use srfi-69 rb-tree)

(define VERTICES 2500)
(define EDGES 100)

(define g (make-ephemeral-map (lambda (x y) (- x y))))

(define (insert-edges)
  (display "\n RB-tree - Inserting edges\n")
  (do ((i 0 (+ i 1))) ((= i VERTICES))
    (do ((j 1 (+ j 1))) ((= j EDGES))
      ((g 'put) i j))))

(insert-edges)


$ csc -O2 rb-tree.scm -o rb-tree
$ time ./rb-tree 

 RB-tree - Inserting edges

.... hanging until now: more than 15 minutes!!!