some common lisp stuffs

example.lsp

(defun our-copy-tree (tr)
  (if (atom tr)
      tr
      (cons (our-copy-tree (car tr))
            (our-copy-tree (cdr tr)))))

(defun get_max_v1 (lst)
  (if (null lst)
      "没有要比较的元素"
      (if (null (cdr lst))
          (car lst)
          (if (> (car lst) (get_max_v1 (cdr lst)))
              (car lst)
              (get_max_v1 (cdr lst))))))


(get_max_v1 '())
(get_max_v1 '(123 465 32476 29715))
(get_max_v1 '(2 56 7 188 76 76 62))




(defun maximum (lst)
  (if (null lst)
      nil
      (let ((tail-max (maximum (cdr lst))))
        (if (> (car lst) tail-max)
            (car lst)
            tail-max))))

(maximum '())
(maximum '(123 465 32476 29715))
(maximum '(2 56 7 188 76 76 62))


(defun fac(n)
  (if (= n 0)
      1
      (* n (fac (- n 1)))))

(defun fact(n)
  (fac-s n 1))

(defun fac-s (n acc)
  (if (= n 0)
      acc
      (fac-s (- n 1) (* acc n))))