Re: [請益] 沒有想像中簡單的小問題

[yauhh (喲)]

ANSI Common-Lisp 版本:

(setf x '(3 4 5 6 7))

(defun repeat-cdr (x i)
        (cond ((= i 0) x)
                (t (repeat-cdr (cdr x) (- i 1)))
        )
)

(defun item (x i)
        (cond ((= i 1) (cons (car x) nil))
                (t (append (item x (- i 1)) (cons (car (repeat-cdr x (- i 1))) nil)))
        )
)

(defun ascend (n)
        (cond ((= n 1) (cons n nil))
                (t (append (ascend (- n 1)) (cons n nil)))
        )
)

(defun palindrome (n)
        (cond ((= n 1) (cons n nil))
                (t (append (ascend (- n 1)) (cons n nil) (reverse (ascend (- n 1)))))
        )
)

(defun odd-size (x)
        (cond ((null (car x)) nil)
                ((= 0 (mod (length (car x)) 2)) (odd-size (cdr x)))
                (t (cons (car x) (odd-size (cdr x))))
        )
)

(defun diamond (x)
        (odd-size (mapcar #'(lambda (y) (item x y)) (palindrome (length x))))
)

(defun print* (x)
        (cond ((atom x) (princ x))
                ((listp x) (mapcar #'(lambda (y) (print* y)) x) (terpri))
        )
)

(defun repeat-print (x i)
        (cond ((< i 1) nil)
                ((= i 1) (princ x))
                (t (repeat-print x (- i 1)) (princ x))
        )
)

(mapcar #'(lambda (y) (repeat-print #\space (/ (- (length x) (length y)) 2))
(print* y)) (diamond x))


--
※ 發信站: 批踢踢實業坊(ptt.cc) 
◆ From: 59.112.224.95
推 buganini:忽然有點想po一篇偽whitespace版XD
→ buganini:算了怕被噓:p
推 yoco315:whitespace 好阿 XDDD