(defun raise-loop (n m)
  (let ((out 1))
    (dotimes (i m out)
      (setf out (* out n)))))

(defun raise-recurse1 (n m)
  (if (< m 1)
      1
      (* n (raise-recurse1 n (1- m)))))

(defun raise-recurse2 (n m &optional (out 1))
  (if (< m 1)
      out
      (raise-recurse2 n (1- m) (* n out))))

(defun raise-helper (n m)
  (labels ((worker (m1 out)
	     (if (< m1 1)
		 out
		 (worker (1- m1) (* n out)))))
    (worker m 1)))

(defun visit (fn x)
  (if (atom x)
      (funcall fn x)
      (dolist (one x)
	(visit fn one))))

(defun count-anywhere (l goal)
  (let ((out 0))
    (labels ((count1 (x) (if (eql x goal) 1 0))
	     (counts (x) (incf out (count1 x))))
      (visit #'counts l)
      out)))
                                                                                                                                                                                
;; CL-USER> (raise-loop 2 3)
;; 8
;; CL-USER> (raise-recurse1 2 3)
;; 8
;; CL-USER> (raise-recurse2 2 3)
;; 8
;; CL-USER> (raise-helper 2 3)
;; 8
;; CL-USER> (raise-helper 2 4)
;; 16
;; (count-anywhere '((c 1 ) (((c  d c) e ) c) c (c (c ))) 'c)
;; 7

(defun median (num-set)
  (let* ((num-set    (sort num-set #'<))
         (set-length (length num-set))
         (middle     (truncate set-length 2)))
    (if (oddp set-length)
        (nth  middle num-set)
        (/ (+ 
	    (nth middle num-set) 
	    (nth (- middle 1) num-set)) 
	   2))))