Hailstone Numbers

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

Problem type

Pick a positive integer nn. If it is odd, multiply it by three and then add one. If nn is even, divide it by two. The positive integer obtained is the new nn, and this is repeated until the number becomes 1. Given the value of nn, with 1 \le n< 2^{31}1 \le n< 2^{31}, determine the number of operations before nn becomes 1.

Sample Input


Sample Output



nn will become 10, 5, 16, 8, 4, 2, then 1, which is a total of 7 operations.


  • 6
    jason6  commented on Oct. 27, 2018, 6:06 p.m.

    Collatz Conjecture!

    • 1
      SeanJxie  commented on Dec. 18, 2019, 10:04 a.m.

      Someone has been watching NumberPhile!

  • 4
    aeternalis1  commented on Nov. 18, 2017, 10:14 a.m. edited

    For the full explanation:

    1. Stop asking for help in comments.

    2. Go to https://slack.dmoj.ca/ and ask for help in the #help channel.