RosettaCodeData/Task/Balanced-brackets/EchoLisp/balanced-brackets.echolisp

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(define (balance str)
(for/fold (closed 0) ((par str))
#:break (< closed 0 ) => closed
(+ closed
(cond
((string=? par "[") 1)
((string=? par "]") -1)
(else 0)))))
(define (task N)
(define str (list->string (append (make-list N "[") (make-list N "]"))))
(for ((i 10))
(set! str (list->string (shuffle (string->list str))))
(writeln (if (zero? (balance str)) '👍 '❌ ) str)))
(task 4)
❌ "[]]][[]["
❌ "]][][[[]"
❌ "][[[]]]["
👍 "[][[[]]]"
❌ "]][[][]["
❌ "][][[[]]"
👍 "[][][[]]"
❌ "]][[][[]"
❌ "[[]]][[]"
❌ "[[][]]]["