CCC '10 J1 - What is n, Daddy?

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Points: 3
Time limit: 2.0s
Memory limit: 64M

Problem type
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Canadian Computing Competition: 2010 Stage 1, Junior #1

Natalie is learning to count on her fingers. When her Daddy tells her a number n (1 \le n \le 10), she asks "What is n, Daddy?", by which she means "How many fingers should I hold up on each hand so that the total is n?"

To make matters simple, her Daddy gives her the correct finger representation according to the following rules:

  • the number may be represented on one or two hands;
  • if the number is represented on two hands, the larger number is given first.

For example, if Natalie asks "What is 4, Daddy?", her Dad may reply:

  • 4 is 4.
  • 4 is 3 and 1.
  • 4 is 2 and 2.

Your job is to make sure that Natalie's Daddy gives the correct number of answers.

Input Specification

The input will be a single integer i such that 1 \le i \le 10.

Output Specification

The output is the number of ways of producing that number on two hands, subject to the rules outlined above.

Sample Input


Output for Sample Input



  • 1
    devarshi  commented on May 12, 2020, 11:20 p.m.

    Would you show 5 on the right hand and then on the left? Does that count as 1 possibility?

    • 1
      hjanday  commented on May 13, 2020, 10:28 a.m.

      Any duplicate cases would only be counted once.

  • -1
    alihu264  commented on April 26, 2020, 8:48 p.m.

    how did I get stumped for 20 minutes on a 3 pointer

  • 2
    jorispos  commented on Feb. 19, 2019, 6:32 p.m.

    Can anyone check my solution? Is there any other (maybe mathematical) way to solve this?

    • 5
      kingW3  commented on Feb. 19, 2019, 7:02 p.m.

      If you're looking for more mathematical solution try thinking about the same problem but make the number of fingers also a parameter. Instead of it being 5 and make n\leq2k.

  • -4
    Arihan10  commented on Feb. 9, 2019, 5:32 p.m.

    Can more sample testcases please be added to this problem? Thanks.

    • -3
      Robloxian  commented on Feb. 9, 2019, 7:03 p.m.

      Is making your own test cases that hard

  • -6
    Deathheart270  commented on Jan. 30, 2019, 12:05 p.m. edited

    This comment is hidden due to too much negative feedback. Click here to view it.

  • 83
    CarolChen  commented on Feb. 15, 2016, 11:55 a.m. edited

    Could not figure out what I was doing wrong then I remembered we have only 5 fingers.

    • 3
      MakanDey  commented on Feb. 22, 2018, 11:29 a.m.

      Oh darn I thought I had 40.

    • 1
      retronerd2016  commented on Nov. 2, 2017, 5:52 p.m.

      wait hold on the example says 3, what does 3 mean

      • 10
        xxsc  commented on July 3, 2018, 11:19 p.m. edited

        3 is the number of ways to show 4.

        4 is 4 is one way.

        4 is 3 and 1 is another.

        4 is 2 and 2 is the last one, because saying 4 is 1 and 3 would be the same as saying 4 is 3 and 1. Same goes with 4 is 0 and 4.


        Yes CarolChen that is helpful.

    • 3
      Alicia  commented on Oct. 31, 2017, 11:59 p.m.

      @ CarolChen that's a very helpful hint, thanks

    • 6
      Epic1Online  commented on Oct. 30, 2017, 4:25 p.m.

      That was a very helpful comment thanks!