IO probe for GCJ

io-probe.el

(require 'cl-lib)

(defun read-next-word ()
  (let ((end (progn (forward-word)
                    (point)))
        (start (progn (backward-word)
                      (point))))
    (forward-word)
    (buffer-substring start end)))

(defun read-next-number ()
  (string-to-number (read-next-word)))

(defun find-two-purchases (c k ps)
  (let ((result nil))
    (cl-loop for i from 0 to (- k 2)
             until result
             do (cl-loop
                 for j from (1+ i) to (1- k)
                 until (= (+ (aref ps i) (aref ps j)) c)
                 finally do (setq result (cons i j))))
    result))

(defun solve ()
  (interactive)
  (let ((input-buffer (find-file-noselect "input.txt"))
        (output-buffer (find-file-noselect "output.txt")))
    (with-current-buffer output-buffer
      (erase-buffer))

    (with-current-buffer input-buffer
      (goto-char (point-min))
      (let ((n (read-next-number)))
        (dotimes (u n)
          (let* ((c (read-next-number))
                 (k (read-next-number))
                 (ps (apply #'vector
                            (cl-loop
                             for i from 1 to k
                             collect (read-next-number))))
                 (result (find-two-purchases c k ps)))
            (with-current-buffer output-buffer
              (insert (format "Case #%d: %d %d\n"
                              (1+ u)
                              (1+ (car result))
                              (1+ (cdr result))))
              (save-buffer))))))))