Statistics

Problem Statement for "RemoveDigits"

Problem Statement

Given a non-negative integer n (n may have up to 50 digits) and another number m, remove exactly m digits from n so the remaining number is as big as possible. m will always be less than the number of digits in n.

Create a class RemoveDigits containing the method maxNumber which takes a String n and an int m and returns a String containing the biggest number when removing exactly m digits from n.

Definition

Class:
RemoveDigits
Method:
maxNumber
Parameters:
String, int
Returns:
String
Method signature:
String maxNumber(String n, int m)
(be sure your method is public)

Notes

  • n may contain leading zeros, see example 1.
  • The return value should contain exactly |n|-m digits, where |n| is the number of digits in n.

Constraints

  • n will contain between 1 and 50 characters, inclusive.
  • n will only contain digits ('0'-'9').
  • m will be between 0 and |n|-1, inclusive, where |n| is the number of digits in n.

Examples

  1. "834391370"

    2

    Returns: "8491370"

    We should try to get the highest digits in the front. It's not possible to get the 9 in the front since that would require removing 4 digits, so we have to be satisfied with the 8. We still can't get the 9 to the second place in the final number, so the 4 is the highest choice for this position and thus we remove the digit 3. Now we can get the 9 as the third digit from the left in the final number by removing the second digit 3. Now we have removed 2 digits, and the number remaining is 8491370.

  2. "0021597002943020"

    3

    Returns: "2597002943020"

    We start with removing the two leading zeros and then the first 1, thus getting 2597002943020.

  3. "0000500390"

    2

    Returns: "00500390"

  4. "91459800928398113866079548895152924499"

    22

    Returns: "9999995152924499"

  5. "98"

    1

    Returns: "9"

  6. "5574742579580037796"

    5

    Returns: "77579580037796"

  7. "9"

    0

    Returns: "9"

  8. "97196906765509955148247685136485989590567213"

    24

    Returns: "99999888989590567213"

  9. "045976155811530869432464"

    21

    Returns: "996"

  10. "5042704197833986905959"

    3

    Returns: "5704197833986905959"

  11. "46015497067739966839147010850932314827724"

    6

    Returns: "97067739966839147010850932314827724"

  12. "837050534000993078357423071802503680066009"

    32

    Returns: "9988866009"

  13. "5913923747221068072017099345521753667"

    26

    Returns: "99995753667"

  14. "681"

    2

    Returns: "8"

  15. "421419323596316821426638394694"

    6

    Returns: "933596316821426638394694"

  16. "53629987"

    0

    Returns: "53629987"

  17. "97153"

    4

    Returns: "9"

  18. "07528682747096067186314583904499"

    4

    Returns: "8682747096067186314583904499"

  19. "51105949004125"

    2

    Returns: "515949004125"

  20. "4532805243631322601073622502317899126"

    28

    Returns: "877899126"

  21. "79419286675357073617180186979768641433121839086"

    29

    Returns: "999986443321839086"

  22. "27101821"

    0

    Returns: "27101821"

  23. "735674297930366516473023942133059"

    1

    Returns: "75674297930366516473023942133059"

  24. "858305306098129664314486"

    22

    Returns: "99"

  25. "203516274775843435431"

    1

    Returns: "23516274775843435431"

  26. "35173303638285773727812555"

    4

    Returns: "7333638285773727812555"

  27. "3519988270381272986302275"

    9

    Returns: "9988872986302275"

  28. "0053713395864221963086642659889255782345353"

    37

    Returns: "999985"

  29. "931327225382557685702445340295"

    0

    Returns: "931327225382557685702445340295"

  30. "91228486230828791783122"

    3

    Returns: "98486230828791783122"

  31. "5"

    0

    Returns: "5"

  32. "2260280513100029014888065551395552151441018"

    0

    Returns: "2260280513100029014888065551395552151441018"

  33. "8367212524761746221169322432511"

    13

    Returns: "877762269322432511"

  34. "9404726293910"

    4

    Returns: "976293910"

  35. "5906208116615"

    8

    Returns: "98665"

  36. "2760764491237019"

    7

    Returns: "791237019"

  37. "55878243502579215533780350587"

    2

    Returns: "878243502579215533780350587"

  38. "9218429133958991341631632306872134628"

    33

    Returns: "9999"

  39. "68967749393828728066"

    0

    Returns: "68967749393828728066"

  40. "525479"

    2

    Returns: "5579"

  41. "476479057050978798223962065952324"

    25

    Returns: "99999534"

  42. "86595156412"

    4

    Returns: "9556412"

  43. "460776853273467149443033352630411929436"

    17

    Returns: "9443033352630411929436"

  44. "982349234294189273489273418273489237438"

    38

    Returns: "9"

  45. "5390414380340543465274678742905860863658759366621"

    47

    Returns: "99"

  46. "0"

    0

    Returns: "0"

  47. "00"

    1

    Returns: "0"

  48. "789"

    2

    Returns: "9"

  49. "99999999999999999999999999999999999999999999999999"

    1

    Returns: "9999999999999999999999999999999999999999999999999"

  50. "987"

    1

    Returns: "98"

  51. "1337"

    0

    Returns: "1337"

  52. "123"

    0

    Returns: "123"

  53. "9999"

    1

    Returns: "999"

  54. "9999999999999999999999999999999999999999"

    5

    Returns: "99999999999999999999999999999999999"

  55. "001100"

    5

    Returns: "1"

  56. "999999"

    3

    Returns: "999"

  57. "1928374656473625278234"

    13

    Returns: "987778234"

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