Statistics

Problem Statement for "TheAlmostLuckyNumbers"

Problem Statement

A lucky number is a number whose decimal representation contains only the digits 4 and 7. An almost lucky number is a number that is divisible by a lucky number. For example, 14, 36 and 747 are almost lucky, but 2 and 17 are not. Note that a number can be both lucky and almost lucky at the same time (for example, 747).

You are given longs a and b. Return the number of almost lucky numbers between a and b, inclusive.

Definition

Class:
TheAlmostLuckyNumbers
Method:
count
Parameters:
long, long
Returns:
long
Method signature:
long count(long a, long b)
(be sure your method is public)

Constraints

  • a will be between 1 and 10,000,000,000, inclusive.
  • b will be between a and 10,000,000,000, inclusive.

Examples

  1. 1

    10

    Returns: 3

    There are three almost lucky numbers less than or equal to ten - 4, 7 and 8.

  2. 14

    14

    Returns: 1

    14 is an almost lucky number.

  3. 1

    100

    Returns: 39

  4. 1234

    4321

    Returns: 1178

  5. 1

    3

    Returns: 0

  6. 1

    10000000000

    Returns: 3823045312

  7. 123456789

    987654321

    Returns: 330386840

  8. 1

    1

    Returns: 0

  9. 1000000000

    1000000000

    Returns: 1

  10. 4

    4

    Returns: 1

  11. 2

    2

    Returns: 0

  12. 3

    3

    Returns: 0

  13. 999970000

    999999999

    Returns: 11462

  14. 44

    77

    Returns: 15

  15. 48

    73

    Returns: 10

  16. 757148

    167851001

    Returns: 63880759

  17. 301413357

    336971125

    Returns: 13593801

  18. 160567226

    659598369

    Returns: 190781558

  19. 4890852

    391749388

    Returns: 147897472

  20. 26239573

    35766291

    Returns: 3642006

  21. 597007

    473038165

    Returns: 180616328

  22. 3615545

    326051437

    Returns: 123268713

  23. 118341523

    392289611

    Returns: 104731438

  24. 37215529

    170427799

    Returns: 50927765

  25. 168544291

    675016434

    Returns: 193626376

  26. 683447134

    950090227

    Returns: 101939155

  27. 82426873

    116752252

    Returns: 13122652

  28. 194041605

    706221269

    Returns: 195808401

  29. 69909135

    257655784

    Returns: 71776471

  30. 21417563

    84970744

    Returns: 24296649

  31. 4735993214

    5788109700

    Returns: 402228932

  32. 3788115833

    8956428880

    Returns: 1975870108

  33. 1662213698

    6214162788

    Returns: 1740230313

  34. 3951218642

    6331312118

    Returns: 909920679

  35. 1543831757

    5048844734

    Returns: 1339982138

  36. 1284888887

    5105102205

    Returns: 1460485012

  37. 4565962192

    7762163387

    Returns: 1221922073

  38. 8735993214

    9788109700

    Returns: 402229076

  39. 8788115833

    9956428880

    Returns: 446651414

  40. 8662213698

    9214162788

    Returns: 211012663

  41. 8951218642

    9331312118

    Returns: 145311415

  42. 8543831757

    9048844734

    Returns: 193068806

  43. 8284888887

    9105102205

    Returns: 313571473

  44. 8565962192

    9762163387

    Returns: 457313225

  45. 5000000000

    10000000000

    Returns: 1911522647

  46. 9000000000

    10000000000

    Returns: 382304516

  47. 4444444444

    7777777777

    Returns: 1274348603

  48. 999

    10000000000

    Returns: 3823044930

  49. 1000000000

    10000000000

    Returns: 3440740760

  50. 3

    1234567891

    Returns: 471980733

  51. 123

    9991999997

    Returns: 3819986852

  52. 9999

    10000000000

    Returns: 3823041489

  53. 5

    10000000000

    Returns: 3823045311

  54. 9999999999

    10000000000

    Returns: 1

  55. 2341243

    10000000000

    Returns: 3822150237

  56. 5

    9987654321

    Returns: 3818325523

  57. 515151515

    10000000000

    Returns: 3626100495

  58. 1

    1000000000

    Returns: 382304553

  59. 4745

    4474745457

    Returns: 1710713382

  60. 100

    10000000000

    Returns: 3823045274

  61. 1234567890

    9876543210

    Returns: 3303866595

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