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  1. t = Integer(gets)
  2. while t > 0
  3. a4 = []
  4. a7 = []
  5. n = Integer(gets)
  6. i = 1
  7.  
  8. while i <= n 
  9. a4 << i.to_s.count("4")
  10. a7 << i.to_s.count("7")
  11.  
  12. i = i + 1
  13. end
  14. count = 0 
  15. i = 1
  16. while ( i<=n)
  17. if a4[i] == a7[i]
  18. count = count + 1
  19. end
  20. i =i + 1
  21. end
  22. count = count*(count-1)/2
  23. print "#{count}\n" 
  24. t = t - 1
  25. end
Success #stdin #stdout 0s 4760KB
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stdout
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https://ideone.com/R06xU
language:
Ruby (ruby 2.5.5)
created:
14 years ago
visibility:
public

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