Statistics

Problem Statement for "BooksNumbering"

Problem Statement

A new library was founded in our city. The books were labeled 1, 2, 3, 4, etc., with no leading zeroes. A total of usedDigits digits were used to create the labels. Return the total number of books in the library, or -1 if usedDigits does not correspond to a valid solution.

Definition

Class:
BooksNumbering
Method:
numberOfBooks
Parameters:
int
Returns:
int
Method signature:
int numberOfBooks(int usedDigits)
(be sure your method is public)

Constraints

  • usedDigits will be between 1 and 2 * 109, inclusive.

Examples

  1. 11

    Returns: 10

    Each of the first 9 numbers (1-9) contain one digit. Number 10 contains 2 digits. Therefore, there's a total of 11 digits.

  2. 10

    Returns: -1

    There is no possible solution. It takes 9 digits to label 9 books, and 11 digits to label 10 books.

  3. 189

    Returns: 99

  4. 192

    Returns: 100

  5. 1999999998

    Returns: 234567900

  6. 2000000000

    Returns: -1

  7. 7

    Returns: 7

  8. 1

    Returns: 1

  9. 1863927342

    Returns: 219448716

  10. 1863927343

    Returns: -1

  11. 9

    Returns: 9

  12. 99

    Returns: 54

  13. 999

    Returns: 369

  14. 9999

    Returns: -1

  15. 99999

    Returns: 22221

  16. 999999

    Returns: 185184

  17. 9999999

    Returns: -1

  18. 99999999

    Returns: -1

  19. 999999999

    Returns: 123456789

  20. 189

    Returns: 99

    99

  21. 2889

    Returns: 999

    999

  22. 38889

    Returns: 9999

    9999

  23. 488889

    Returns: 99999

    99999

  24. 5888889

    Returns: 999999

    999999

  25. 68888889

    Returns: 9999999

    9999999

  26. 788888889

    Returns: 99999999

    99999999

  27. 192

    Returns: 100

    100

  28. 2893

    Returns: 1000

    1000

  29. 38894

    Returns: 10000

    10000

  30. 488895

    Returns: 100000

    100000

  31. 5888896

    Returns: 1000000

    1000000

  32. 68888897

    Returns: 10000000

    10000000

  33. 788888898

    Returns: 100000000

    100000000

  34. 12

    Returns: -1

  35. 10

    Returns: -1

  36. 193

    Returns: -1

  37. 191

    Returns: -1

  38. 2896

    Returns: -1

  39. 2891

    Returns: -1

  40. 38897

    Returns: -1

  41. 38891

    Returns: -1

  42. 488898

    Returns: -1

  43. 488890

    Returns: -1

  44. 5888902

    Returns: -1

  45. 5888890

    Returns: -1

  46. 68888904

    Returns: -1

  47. 68888890

    Returns: -1

  48. 788888900

    Returns: -1

  49. 788888894

    Returns: -1

  50. 756419241

    Returns: 95941293

  51. 756419240

    Returns: -1

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