CFLP 7

;Problema [1]

(defun suma(l)

    (apply '+ (remove-if-not '(lambda (x) (evenp (position x l))) l))

)

;EXEMPLU
;(suma '(1 2 3 4 5))
;9
;> (suma '(0 1 0 1 0 1))
;0
;>
;____________________________________________________________________

;Problema [2]

;(rot-left '(a b c) 1)
;(B C A)
;> (rot-left '(a b c) 2)
;(C A B)
;>

(defun rot-right (lista n)
    (cond

    ((= n 0) lista)
    (t (rot-right (append (last lista) (reverse (cdr (reverse lista)))) (- n 1)))

    )

)
;(rot-right '(a b c) 1)
;(C A B)
;> (rot-right '(a b c) 2)
;(B C A)
;>
;____________________________________________________________________

;Problema [3]

 (defun aparitii (lista x)
    (setq count 0)
    (car (last (mapcar '(lambda (i) (if (= i x) (setq count (+ count 1)))) lista)))
)
;EXEMPLU:
;>(lungimi '((b c) (d e f)) '())
;(2 3)
;> (lungimi '((b c) d e (f) g (h i j)) '())
;(2 1 3)
;>
;> (lungimi '(a b c) '())
;NIL
;____________________________________________________________________

;Problema [4]

;(presentp '(a (b c)) 'b)
;T
;> (presentp '(a (b c) (d e f) (g)) 'f)
;T
;>
;____________________________________________________________________

;Problema [5]

(defun cifre (x lista)

    (cond

    ((= x 0) lista)
    (t (cifre (floor (/ x 10)) (append (list (mod x 10)) lista)))

    )

)

;> (cifre 3548 '())
;(3 5 4 8)
;____________________________________________________________________

;Problema [6]

(defun pozpar (lista)

    (do ( (i 1 (+ i 1)) (l lista (cdr l)) (listai '() ) )

        ((null l) listai)
        (if (not (= (mod i 2) 0)) (setq listai (append listai (list (car l)))))
    )

)

;> (pozpar '(1 2 3 4 5 6 7))
;(1 3 5 7)
;____________________________________________________________________

;Problema [7]

(defun cmmdc (x y)

    (do ( (a x) (b y) )

        ((= a b) a)
        (if (> a b) (setq a (- a b)) (setq b (- b a)))

    )

)

;> (cmmdc 25 5)
;5
;> (cmmdc 3 27)
;3
;____________________________________________________________________