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  1. -- http://i...content-available-to-author-only...e.com/sZ9tiN
  2. import Data.List
  3. import Data.Maybe
  4. checkBraces "" = True
  5. checkBraces e = checkBrace e [] where
  6. 	openBraces = "({["
  7. 	closeBraces = ")}]"
  8. 	braceToBrace fromBraces toBraces brace = toBraces!!(fromJust $ elemIndex brace fromBraces)
  9. 	otcBrace = braceToBrace openBraces closeBraces
  10. 	checkBrace (c:e) s | elem c openBraces = checkBrace e ((otcBrace c):s)
  11. 	checkBrace (c:e) (h:s) | (elem c closeBraces) && (h==c) = checkBrace e s
  12. 	checkBrace (_:e) _ = False
  13. 	checkBrace [] [] = True
  14. 	checkBrace [] _ = False
  15. main = mapM_ (print . checkBraces) bracesExpressionExamples where
  16. 	bracesExpressionExamples = 
  17. 		[
  18. 			"({[{}]{}[]})",
  19. 			"({}}{[{}]{}[]})",
  20. 			"({[{}]{}[]}",
  21. 			"({[{}]{}]})",
  22. 			"({[{}{}[]})",
  23. 			"",
  24. 			"{}"
  25. 		]
Success #stdin #stdout 0s 6220KB
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https://ideone.com/sZ9tiN
language:
Haskell (ghc 8.4.4)
created:
12 years ago
visibility:
public

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