1. A – Content Too Large
累積和を比較して、常にMを超えないという条件でループしました。
(defun put-all-p (M An)
(loop for a in An
sum a into S
always (<= S M)))
;; (put-all-p 15 '(3 1 4 1 5)) ;=> T
(defun print-yesno (c)
(declare (type boolean c))
(princ (if c "Yes" "No")))
(defun main ()
(let* ((N (read))
(M (read))
(An (loop repeat N collect (read))))
(print-yesno (put-all-p M An))))
#-swank(main)Code language: Lisp (lisp)
2. B – π
これは、計算式を表示するだけです。
浮動小数点数の表示だけ、少し工夫があります。
(defun circle-area (r)
(* pi (* r r)))
(defun main ()
(let ((D (read)))
(format t "~f" (circle-area (/ D 2)))))
#-swank(main)Code language: Lisp (lisp)
3. C – Four Hidden
0〜（|T| – |U|)まで順にスキャンして、二重ループでチェックしました。
;; (continous-substring-p "tak??a?h?" "nashi") ;=> T
;; (continous-substring-p "??e??e" "snuke") ;=> NIL
(defun continous-substring-p (TT U)
(loop for i from 0 to (- (length TT) (length U))
thereis (and (or (char= (char TT i) (char U 0))
(char= (char TT i) #\?))
(loop for j from 0 below (length U)
always (or (char= (char TT (+ i j))
(char U j))
(char= (char TT (+ i j))
#\?))))))
(defun print-yesno (c)
(declare (type boolean c))
(princ (if c "Yes" "No")))
(defun main ()
(let* ((TT (read-line))
(U (read-line)))
(print-yesno (continous-substring-p TT U))))
#-swank(main)
Code language: Lisp (lisp)
4. D – Who is Missing?
まずはハッシュテーブルに数値を記録して、記録されていない数値を集めました。
(defun missing-list (N Am)
(let* ((ht (make-hash-table)))
(loop for a in Am
do (setf (gethash a ht) t))
(loop for i from 1 to N
when (null (gethash i ht))
collect i)))
;; (missing-list 10 '(3 9 2)) ;=> (1 4 5 6 7 8 10)
(defun main ()
(let* ((N (read))
(M (read))
(Am (loop repeat M
collect (read)))
(Xc (missing-list N Am)))
(princ (length Xc))
(terpri)
(loop for x in Xc
do (princ x)
(princ #\space))))
#-swank(main)Code language: Lisp (lisp)
5. E – Festival
逆順にして、「次の花火」を固定してから、遡って「それまでの日数」を記録するようにしました。
;; (next-fireworks 3 '(2 3)) ;=> (1 0 0)
;; (next-fireworks 8 '(1 3 4 7 8)) ;=> (0 1 0 0 2 1 0 0)
(defun next-fireworks (N Am)
(let* ((rev (reverse Am)))
(loop for d from N downto 1
with next = 0
when (and (consp rev) (= (car rev) d))
do (setf next 0)
(pop rev)
collect next into lst
do (incf next)
finally (return (nreverse lst)))))
(defun main ()
(let* ((N (read))
(M (read))
(Am (loop repeat M collect (read))))
(loop for d in (next-fireworks N Am)
do (princ d)
(terpri))))
#-swank(main)Code language: Lisp (lisp)
時間内に全問解答できました。
