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afzalk0001
Known Participant
Aug 9, 2023 11:11 AM UTC
Question

Josephus Problem

100 people standing in a circle in an order 1 to 100. No. 1 has a sword. He kills the next person (i.e. No. 2) and gives the sword to the next (i.e. No. 3). All people do the same until only 1 survives. Which number survives at the last? 
There are 100 people starting from 1 to 100. 

can anyone please tell me how can i do it?

    15 replies

    richardm900458
    richardm900458
    Inspiring
    Aug 9, 2023 11:14 AM UTC

    Thats no appian related question, is it ;)?

      afzalk0001Author
      Known Participant
      Aug 9, 2023 11:16 AM UTC

      No just wanted to try using appian. Whether is it possible using expressuin rules or not?

      stefanhelzle0001
      stefanhelzle0001
      Brainy
      Aug 9, 2023 11:35 AM UTC

      You can implement recursive and iterative algorithms. So, the answer is: Yes!

      mathieud0001
      mathieud0001
      Genius
      Aug 9, 2023 11:46 AM UTC

      Is this some sort of exam question?

      afzalk0001Author
      Known Participant
      Aug 9, 2023 11:49 AM UTC

      Yeah its a puzzle problem. You can refer this - https://www.geeksforgeeks.org/puzzle-100-people-in-a-circle-with-gun-puzzle/

      i was just trying to implement using appian.

      csteward
      csteward
      Brainy
      Aug 9, 2023 3:41 PM UTC

      This is my example with a recursive rule to solve the puzzle (#73).

      As always, make sure to save recursive rules before testing.

      /* rule!chris_test_kc_recur(
      list (Number Array, 1+enumerate(100))
      index (Number, 1)
   )
*/

if(
  count(ri!list)<=1,
  index(ri!list,1,null),
  a!localVariables(
    local!removeIndex: if(
      ri!index=count(ri!list),
      1,
      if(
        ri!index>count(ri!list),
        2,
        ri!index+1
      )
    ),
    local!list: remove(ri!list,local!removeIndex),
    rule!chris_test_kc_recur(
      list: local!list,
      index: local!removeIndex
    )
  )
)

        afzalk0001Author
        Known Participant
        Aug 10, 2023 4:32 AM UTC

        can you please share me the code rule!chris_test_kc_recur? That would be helpful

        richardm900458
        richardm900458
        Inspiring
        Aug 10, 2023 6:55 AM UTC

        why not trying yourself than getting it served already prepared? :) The question was , if it was possible. yes it is. :)

        jamesm4933
        jamesm4933
        Known Participant
        Aug 10, 2023 6:06 PM UTC

        It's called the Josephus Problem.  It was inspired by a story in "The Jewish War" by Flavius Josephus.

        Apparently, the solutions for n=2 up to group size 78 are sequence number A006257 in the On-line Encyclopedia of Integer Sequences

        Wikipedia

        The Jewish War

        nikhilcht188835
        nikhilcht188835
        New Participant
        Aug 11, 2023 5:33 AM UTC

        Here is the solution to your challenge. We have also added a feather so that the user may choose the number of players and who should start the game.

        reduce(
  rule!EI_subEliminateTask(list: _, value: _),
  {
    ldrop(
      enumerate(ri!players) + 1,
      ri!startPlayer - 1
    ),
    if(
      ri!startPlayer = 1,
      {},
      enumerate(ri!startPlayer - 1) + 1
    )
  },
  repeat(ri!players - 1, 0)
)

subrule: rule!EI_subEliminateTask(list: _, value: _),
code: { ldrop(ri!list, 2), ri!list[1] }

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