约瑟夫问题

josephus.scm

(define (f n k)
  (define (f-iter result counter)
    (if (> counter n)
        result
        (f-iter (add1 (modulo (+ result k -1) counter))
                (add1 counter))))
  (f-iter 1 2))

(define (advanced-f prisoners k)
  (define (new-list lst p)
    (append (list-tail lst (add1 p))
            (take lst p)))
  (let* ((len (length prisoners))
         (pos (modulo (- k 1) len)))
    (if (= len 1)
        (display prisoners)
        (begin 
          (display (list-ref prisoners pos))
          (display " ")
          (advanced-f (new-list prisoners pos) k)))))