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Problem Statement for "ClapLight"

Problem Statement

I have a light that changes from on to off or from off to on when I clap twice. The light's sensor samples the noise level in the room at short intervals and it triggers the light to change whenever it detects a low noise level followed by exactly 2 high noise levels followed by a low noise level.

"High" or "low" is based on a threshold noise level. When the sampled noise level is as high or higher than the threshold level, the noise level is classified as "high"; otherwise it is classified as "low". I have a int[] background that is a typical sequence of sensor readings when normal activity is taking place. I want software that will choose the threshold value so that it has the following properties:

  1. 1) It causes more than 50% of all the values in background to be classified "low".
  2. 2) It is the lowest possible threshold value that satisfies the 50% rule and that does not cause background to trigger the light to change.

Create a class ClapLight that contains a method threshold that is given the int[] background and that returns the desired threshold value.

Definition

Class:
ClapLight
Method:
threshold
Parameters:
int[]
Returns:
int
Method signature:
int threshold(int[] background)
(be sure your method is public)

Constraints

  • background will contain between 4 and 50 elements inclusive.
  • Each element of background will be between 0 and 1000 inclusive.

Examples

  1. {6,6,6,6,6}

    Returns: 7

    The threshold must be at least 7 to exceed more than 50% of the samples, and with the threshold set at 7 every reading will be classified "low" and the light will not be triggered.

  2. { 5,8,7,6,12,8,4,3,2,6 }

    Returns: 9

    The threshold must exceed at least 6 of these values to satisfy the 50% rule. So it must be at least 7. But with the threshold set at 7 the sequence 5, 8, 7, 6 would trigger the light. A threshold of 8 will allow the sequence 6,12,8,4 to trigger the light. A threshold of 9 will never cause this sequence to trigger the light.

  3. {8,8,8,1,1,1,1,1,1,1,1,1,1,1,2,1}

    Returns: 2

    Remember that the high noise levels must be both preceded and followed by low noise levels to trigger the light.

  4. {921,1,5,900,8,813,3,3,3,3,3,3,3,813,813}

    Returns: 4

  5. {921,1,5,900,8,813,3,3,3,3,3,3,3,813,813,4}

    Returns: 814

  6. {1,2,3,4}

    Returns: 4

  7. {500,500,500,501,1000,503,500,500,500}

    Returns: 501

  8. {500,500,500,500,1000,503,500,500,500}

    Returns: 504

  9. {500,500,500,500,1000,503,500,500,500,4,4,4,4,4,4,4,4,4,4}

    Returns: 5

  10. {500,500,500,500,1000,503,500,500,500,4,4,4,4,4,4,4,4,4}

    Returns: 504

  11. {500,500,500,500,1000,1000,503,500,500,500,4,4,4,4,4,4,4,4,4}

    Returns: 501

  12. {30,29,28,27,26,25,26,27,28,29,27,11}

    Returns: 29

  13. {1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000,1000}

    Returns: 1001

  14. {18,14,19,23,3,3,3,9,19,12,2,2,1,17,13,9}

    Returns: 14

  15. {18,14,19,23,3,3,3,9,19,12,2,2,1,17,13}

    Returns: 13

  16. {1,1,1,1000,1,1,1,1}

    Returns: 2

  17. {1,1,1,1000,3,1,1,1,1}

    Returns: 4

  18. { 1000, 1000, 1000, 1000 }

    Returns: 1001

  19. { 3, 3, 6, 6 }

    Returns: 7

  20. { 1000, 1000, 1000, 1000, 1000 }

    Returns: 1001

  21. { 0, 0, 1, 1 }

    Returns: 2

  22. { 5, 6, 12, 12, 6 }

    Returns: 13

  23. { 10, 10, 6, 6, 6 }

    Returns: 7

  24. { 0, 1, 2, 3 }

    Returns: 3

  25. { 10, 13, 14, 10 }

    Returns: 14

  26. { 1000, 1000, 1000, 1000, 1000, 1000 }

    Returns: 1001

  27. { 500, 1000, 1000, 500 }

    Returns: 1001

  28. { 0, 0, 0, 4, 4, 0 }

    Returns: 5

  29. { 1000, 1000, 100, 1000, 1000 }

    Returns: 1001

  30. { 1, 5, 6, 1, 1, 1, 1, 1, 1, 1 }

    Returns: 6

  31. { 10, 20, 10, 20 }

    Returns: 21

  32. { 1, 2, 3, 10, 10 }

    Returns: 4

  33. { 4, 8, 1, 4, 9, 6, 2 }

    Returns: 7

  34. { 2, 2, 1, 1, 1 }

    Returns: 2

  35. { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 5, 5, 1, 1, 1, 1, 1 }

    Returns: 6

  36. { 1, 1, 2, 2 }

    Returns: 3

  37. { 0, 1, 0, 1 }

    Returns: 2

  38. { 1, 2, 1, 2 }

    Returns: 3

  39. { 1, 1, 2, 2, 1 }

    Returns: 3

  40. { 6, 6, 6, 8, 8, 8, 6 }

    Returns: 7

  41. { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 5, 5, 1 }

    Returns: 6

  42. { 2, 2, 3, 3 }

    Returns: 4

  43. { 1, 2, 3, 4 }

    Returns: 4

  44. { 0, 0, 0, 0, 0, 10, 30, 0 }

    Returns: 11

  45. { 8, 8, 14, 15 }

    Returns: 15

  46. { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 5, 5, 1 }

    Returns: 6

  47. { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 10, 10, 1 }

    Returns: 11

  48. { 1, 5, 3, 7 }

    Returns: 6

  49. { 1, 4, 5, 6, 2, 3 }

    Returns: 6

  50. { 1, 2, 12, 13 }

    Returns: 13

  51. { 2, 2, 2, 2, 4, 7, 7, 1 }

    Returns: 3

  52. { 2, 2, 3, 3, 2 }

    Returns: 4

  53. { 2, 2, 2, 2, 2, 2, 2, 2, 2, 5, 5 }

    Returns: 3

  54. { 1, 1, 1, 20, 20, 20 }

    Returns: 21

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