結果

問題 No.2053 12345...
コンテスト
ユーザー norioc
提出日時 2025-06-29 17:38:21
言語 Scheme
(Gauche-0.9.15)
結果
AC  
実行時間 571 ms / 2,000 ms
コード長 3,219 bytes
コンパイル時間 251 ms
コンパイル使用メモリ 7,968 KB
実行使用メモリ 67,980 KB
最終ジャッジ日時 2025-06-29 17:38:35
合計ジャッジ時間 11,048 ms
ジャッジサーバーID
（参考情報） 		judge3 / judge2
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ファイルパターン 結果
sample AC * 2
other AC * 31
権限があれば一括ダウンロードができます

ソースコード

diff # 

(use scheme.list)
(use util.match)
(use srfi.13)  ; string
(use srfi.42)  ; list-ec
(use srfi.197) ; chain
(use gauche.collection)
(use gauche.generator)
(use gauche.sequence)

(define input read-line)

(define (ii)
  (string->number (read-line)))

(define (li)
  (let ((s (read-line)))
    (map string->number (string-split s " "))))

(define (prn . args)
  (for-each (lambda (i x)
              (when (> i 0)
                (display " "))
              (display x))
            (iota (length args))
            args)
  (newline))

(define prn* (pa$ apply prn))

(define int string->number)
(define str x->string)

(define-method min ((xs <sequence>))
  (apply min xs))
(define-method max ((xs <sequence>))
  (apply max xs))

(define (minmax . xs)
  (values->list (apply min&max xs)))
(define-method minmax ((xs <sequence>))
  (values->list (apply min&max xs)))

(define (sum xs) (apply + xs))

(define (divmod a b)
  (values->list (div-and-mod a b)))

(define (1+ n) (+ n 1))
(define (1- n) (- n 1))
(define (!= a b) (not (= a b)))

(define pow
  (case-lambda
   ((a b) (expt a b))
   ((a b m) (expt-mod a b m))))

(define isqrt exact-integer-sqrt)

(define ++ string-append)

(define-method frequencies ((xs <sequence>))
  (rlet1 ht (make-hash-table)
    (for-each (^x (hash-table-update! ht x 1+ 0))
              xs)))

(define (pairwise xs)
  (zip xs (cdr xs)))

(define (yn b)
  (prn (if b "Yes" "No")))

(define-macro (input! bindings . body)
  (let loop ((bs (reverse bindings))
             (res '()))
    (if (null? bs)
        `(let*-values ,res
           ,@body)
        (cond
         ((symbol? (car bs))
          (loop (cdr bs)
                (cons `((,(car bs)) (values (ii)))
                      res)))
         ((list? (car bs))
          (loop (cdr bs)
                (cons `(,(car bs) (apply values (li)))
                      res)))
         (else
          'error)))))

(define mlet1 match-let1)

(define (slide xs k :key step)
  (let* ((n (length xs))
         (step (if (undefined? step) k step)))
    (let loop ((xs xs)
               (res '()))
      (if (null? xs)
          (reverse res)
          (loop (drop* xs step)
                (cons (take* xs k) res))))))

(define-macro (mfn pat . body)
  (let ((arg (gensym)))
    `(lambda (,arg)
       (mlet1 ,pat ,arg
         ,@body))))

(define (group xs test)

  (define (sub ys)
    (assume (not (null? ys)))

    (let loop ((g (list (car ys)))
               (ys (cdr ys)))
      (if (null? ys)
          (values (reverse g) ys)
          (match-let1 (y . rest) ys
            (if (test (car g) y)
                (loop (cons y g) rest)
                (values (reverse g) ys))))))

  (if (null? xs)
      '()
      (receive (g rest) (sub xs)
        (if (null? rest)
            (list g)
            (cons g (group rest test))))))

(define (comb n k)
  (if (or (< k 0) (> k n))
      0
      (let loop ((i 0)
                 (num 1)
                 (den 1))
        (if (= i k)
            (/ num den)
            (loop (1+ i)
                  (* num (- n i))
                  (* den (+ i 1)))))))

(let* ((N (ii))
       (A (li)))
  (prn
   (sum-ec (:list g (group A (^(a b) (= (1+ a) b))))
           (comb (length g) 2))))
0