CCC '05 J5 - Bananas

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Points: 10 (partial)
Time limit: 1.0s
Memory limit: 256M
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Canadian Computing Competition: 2005 Stage 1, Junior #5

The term "code monkey" is sometimes used to refer to a programmer who doesn't know much about programming. This is unfair to monkeys, because contrary to popular belief, monkeys are quite smart. They have just been misunderstood. This may be because monkeys do not speak English, but only monkey language. Your job is to help humans and monkeys understand each other by writing a monkey language dictionary. For each word that is typed in, your program must determine whether it is a valid monkey language word.

Unlike in English, spelling in monkey language is very simple. Every word in monkey language satisfies the following rules, and every word satisfying the following rules is a monkey language word.

  1. A monkey language word is a special type of word called an A-word, which may be optionally followed by the letter N and a monkey language word.
  2. An A-word is either only the single letter A, or the letter B followed by a monkey language word followed by the letter S.

Here are some examples:

  • The word A is a monkey language word because it is an A-word.
  • The word ANA is a monkey language word because it is the A-word A followed by the letter N and the monkey language word A.
  • The word ANANA is a monkey language word because it is the A-word A followed by the letter N and the monkey language word ANA.
  • The word BANANAS is a monkey language word because it is an A-word, since it is the letter B followed by the monkey language word ANANA followed by the letter S.

Write a program which accepts words, one word on each line, and for each word prints YES if the word is a monkey language word, and NO if the word is not a monkey language word. The input word X indicates the program should terminate, and there is no output for word X (even though it is not a monkey word).

Sample Input

A
ANA
ANANA
BANANAS
BANANA
X

Sample Output

YES
YES
YES
YES
NO

Comments


  • 0
    yanlin4188  commented on Aug. 14, 2025, 7:07 p.m.

    This question is insane. 1.B A N B A S S. This one is valid if you parse from outside to inside, but invalid if parse left to right. 2.B A S N B A S. This one is completely opposite. so are they both monkeywords?


  • 9
    4EVr_Working  commented on April 26, 2025, 11:40 p.m.

    Since this question seems to be very confusing, I will try to explain it better.

    How to Identify a Monkey Language Word

    A is a monkey language word.

    1. N can separate two monkey language words.

      • Two monkey language words separated by an N (like ANA) are also monkey language words. But if it is not separated by an N (like AA), then it is not a monkey language word.
      • It is not mandatory for an N to be present in a monkey language word (A is a monkey langauge word even though there are no Ns).

    2. B and S can surround a monkey language word. B must be first and S must be anywhere after it.

      • It is not mandatory for a B and an S to be present in a monkey langauge word (A is a monkey langauge word even though there are no Bs and Ss).

    3. Ooo ooo eee eee AH AH is a monkey language word.

    NOTE: All inputs will be capitalized AND will only contain the following letters: A, N, B, and S (and X to denote that the program should terminate, in which case there will be NO output).

    Sample Input

    ANA
BS
AANA
BBANASS
BANASNANANA
ANBANANAS
BANANANANANANBANANANANANBANANASNANANANBANANASNANANANSS
SAB
X

    Sample Output

    YES
NO
NO
YES
YES
YES
NO
NO

    Explanation of Sample Output

    ANA IS a monkey language word because...

    • A is a monkey language word. So ANA is two monkey language words (the As) separated by an N (follows rule #1).
    • This means that it follows ALL THE RULES!

    BS IS NOT a monkey language word because...

    • It is offensive
    • There is no monkey language word between B and S. (Violates rule #2.)

    AANA IS NOT a monkey language word because...

    • There are two As in a row.
      • There is not an N separating them. Two monkey language words must be separated by an N for it to also be a monkey language word. (Violates rule #1.)

    BBANASS IS a monkey language word because...

    • The ANA is two monkey langauge words separated by an N (follows rule #1).
    • The inner B and S surround ANA, which is a monkey language word (follows rule #2).
    • The outer B and S surround BANAS, which we already discovered is a monkey language word (follows rule #2).
    • This means that it follows ALL THE RULES!

    BANASNANANA IS a monkey langauge word because...

    • ANA is two monkey language words separated by an N (follows rule #1).
    • B and S surround ANA, which is a monkey language word (follows rule #2).
    • BANAS and ANANA are both monkey language words and they are separated by an N, so it is valid (follows rule #1).
    • This means that it follows ALL THE RULES!

    ANBANANAS IS a monkey language word because...

    • A is a monkey language word according to the question's description.
    • BANANAS is a monkey language word because the B and the S surround ANANA, which is a monkey language word.
      • ANANA is a monkey language word since it is just three As (and A is a monkey language word) separated by an N (follows rule #1).
    • A and BANANAS are both monkey language words and they are separated by an N (follows rule #1.)
    • This means that it follows ALL THE RULES!

    BANANANANANANBANANANANANBANANASNANANANBANANASNANANANSS IS NOT a monkey language word because...

    • Many things, but if you look at the end, there is NSS, so the N is not followed by a monkey langauge word (SS is not a monkey langauge word for obvious reasons. It literally violates rule #2 and there are no As).

    SAB IS NOT a monkey language word because...

    • The S and B are in the wrong order. The B must go first. (Violates rule #2.)

    NOTE: Words like ANA are STILL monkey language words even though there are no Bs or Ss. Since there are no Bs or Ss, rule #2 is automatically followed.

    This is the same for words like BAS, which is also a monkey language word even though there are no Ns. Since there are no Ns, rule #1 is automatically followed.


  • 0
    y889  commented on Feb. 4, 2025, 3:10 a.m.

    Harder than it looks but easier than you think! Fun question!

    Would've preferred more sample inputs and outputs...


  • 0
    SomethingThatsNotTaken  commented on Jan. 25, 2025, 3:43 a.m.

    To anyone who might be reading this: the input is always uppercase, and it can also be empty


  • 0
    _va  commented on March 31, 2024, 2:48 p.m.

    i think it's hard to study the monkey word :))


  • -3
    Wenhan_Zhang  commented on Jan. 5, 2024, 2:55 a.m. ← edited

    If these are actually monkey words, then BANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANS is a monkey word


    • 17
      mangdani282  commented on Jan. 12, 2024, 4:10 a.m.

      That's not a monkey word. Your word ends in "ANANAS" which is invalid. As stated in the question, a monkey language word containing the letter N must be preceded and followed by another monkey word. The last N is preceded by a monkey language word, but not followed by a monkey language word. All I have to say to you is BANANANANANANBANANANANANBANANASNANANANBANANASNANANANSS.


  • -1
    98765432123456789  commented on Dec. 11, 2023, 2:07 a.m. ← edited

    can someone please help explain/guide me on what's wrong with my code? am i missing an edgecase?

    https://dmoj.ca/src/5992485


    • -1
      98765432123456789  commented on Dec. 11, 2023, 6:48 p.m.

      never mind i found another approach to it


  • 0
    chengtaili2024  commented on Jan. 2, 2023, 2:52 a.m.

    i kept getting the 3rd and 4th case wrong, can someone tell me why I am getting it wrong.


    • 5
      fireheartjerry  commented on Jan. 2, 2023, 10:59 p.m.

      Try the test case BANANASNBANANAS, output should be YES as it is two monkey-language words separated by N.


  • 33
    tappbros  commented on May 17, 2021, 11:20 p.m. ← edited

    I'd have thought monkey language would include "EEE EEE" and "AHH AHH". Well, who am I to judge.

    Edit: (This is a joke to that one guy)


  • 8
    Nils_Emmenegger  commented on May 17, 2021, 3:32 p.m. ← edit 2

    AA is not a monkey language word.

    Also, the largest word in the input is 21 characters long (not including newline).


  • 3
    Leo_Wang_the_king  commented on Jan. 24, 2021, 7:07 p.m.

    is BAS a monkey language word?


    • 6
      Badmode  commented on Jan. 25, 2021, 5:07 p.m.

      Think so.


  • 8
    OneYearOld  commented on Nov. 26, 2020, 9:50 p.m.

    According to CCC test data, blank words and words like "BS" are not monkey language words.


  • -12
    Subway_Man  commented on June 14, 2020, 10:47 p.m.

    This comment is hidden due to too much negative feedback. Show it anyway.


    • 2
      c  commented on June 15, 2020, 1:19 a.m.

      We take official problem statements from the CCC. Unless there are significant issues with the problem statement, we don't change it.

      The problem statement gives a clear input and output specification, even if it doesn't exist as a heading so I do not see the problem.


      • -12
        Subway_Man  commented on June 15, 2020, 6:51 a.m.

        This comment is hidden due to too much negative feedback. Show it anyway.


        • -7
          injust  commented on June 15, 2020, 3:58 p.m.

          This comment is hidden due to too much negative feedback. Show it anyway.


        • 3
          AlanL  commented on June 15, 2020, 3:10 p.m.

          Aren't all letters uppercase though? I don't even think there is a case where they're lowercase.


  • 4
    David1425  commented on Feb. 9, 2020, 8:57 p.m.

    Is "BBBBASSSS" a monkey word?


    • 1
      AlanL  commented on Feb. 9, 2020, 9:08 p.m.

      Yes


  • -2
    Togohogo1  commented on Dec. 24, 2019, 2:07 a.m.

    Is BANASSNBBANAS a monkey word?


  • 1
    4fecta  commented on June 8, 2019, 7:08 p.m.

    I keep getting WA on the last case. Can anyone give me a hint as to what I am doing wrong?


    • 11
      lookcook  commented on June 8, 2019, 8:46 p.m.

      Try inputting "BANSA" into your program. It should output "NO" because the B and S are not separated by a monkey word.


      • 2
        4fecta  commented on June 8, 2019, 9:14 p.m.

        Thank you for spotting my error.


  • 3
    anasschoukri2  commented on Aug. 22, 2017, 3:05 p.m.

    ANABANANAS is a monkey word ??


    • 4
      aeternalis1  commented on Aug. 22, 2017, 4:20 p.m. ← edited

      No, because the two monkey words ('ANA' and 'BANANAS') aren't separated by an 'N'.


  • 0
    susheelk  commented on Feb. 15, 2017, 10:50 p.m. ← edited

    Is BANANASNBANANAS a monkey language word?


    • 0
      Selena_Liu  commented on July 7, 2017, 11:47 p.m.

      should be since it's a monkey-language word (BANANAS) followed by N, then by another monkey-language word.


  • 0
    TheKrishnan  commented on Feb. 9, 2017, 8:37 p.m.

    Is BBANANASS a monkey language word?


    • 0
      george_chen  commented on Feb. 9, 2017, 9:44 p.m.

      Yes because it is a 'B' followed by a monkey language word ("BANANAS") and followed by 'S'


  • 0
    septence123  commented on Jan. 22, 2017, 6:14 p.m.

    Is ANAANA a monkey language word?If not why?


    • 2
      Kirito  commented on Jan. 22, 2017, 6:47 p.m.

      No, since the two A words ANA do not have an N between them


  • -5
    Eli  commented on Feb. 2, 2015, 11:50 p.m.

    This comment is hidden due to too much negative feedback. Show it anyway.


    • 0
      Xyene  commented on Feb. 27, 2015, 5:01 p.m.

      You may now use System.exit; I've patched it to work.


    • 4
      FatalEagle  commented on Feb. 3, 2015, 12:23 a.m.

      We block System.exit for security reasons.

      On the other hand, you could always use C++ and std::exit.


      • 14
        Sentient  commented on Feb. 3, 2015, 12:46 a.m.

        For Java, you could just use return to exit the main method, which will terminate the program


  • -14
    Yuting9  commented on Nov. 20, 2014, 1:12 a.m.

    This comment is hidden due to too much negative feedback. Show it anyway.


    • 5
      FatalEagle  commented on Nov. 20, 2014, 2:17 a.m.

      No, they are not monkey language words.