(use scheme.list)
(use util.match)

(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 (min&max* xs) (apply min&max xs))


(define (solve)
  (let ((xs (li)))
    (receive (a b) (min&max* xs)
      (- b a))))

(let ((t (ii)))
  (dotimes (_ t)
    (prn (solve))))