CCCHK '08 J2 - Lucky Number

View as PDF

Submit solution

Points: 3
Time limit: 1.0s
Memory limit: 64M

Problem type

In ancient Europe, people believed that their luck was dependent on a number. By summing up the digits of their birthday, they got a sum. By repeatedly adding the digits of the sum until a single digit number remains. This resultant number was called the "single digit representation". And the digit reflected their luck in their whole life.

In this question, a birthday will be given by a non-negative integer x (\le 10\,000 digits). Your program has to compute the single digit representation of the given number. Example:

1 \to 1
10 \to 1+0 = 1
19 \to 1+9 = 10 \to 1
999 \to 9+9+9 = 27 \to 9

Input Specification

The first input is an integer specifying the number of test cases. Then each input number appears on a line by itself.

Output Specification

For each test case, output the single digit representation of it.

Sample Input


Sample Output



  • 0
    Fares_X  commented on Dec. 10, 2022, 2:59 p.m.

    This kind of number is better known as "digital root" (999, anyone?)

  • 2
    Goat_dy  commented on Aug. 27, 2019, 3:19 p.m.

    Why do I keep getting IRs?

    • 4
      hxxr  commented on Aug. 27, 2019, 4:22 p.m. edit 2

      The input integers can be up to 10\,000 digits long. Integer.parseInt() cannot parse integers from the input greater than 2\,147\,483\,647.

      And in fact you cannot store a 10\,000 digit number as an int or even a long. Consider storing it as a String.

  • -4
    cardistryMagic  commented on March 14, 2017, 11:40 a.m. edited

    l o L

    • 5
      Xyene  commented on March 14, 2017, 12:30 p.m.

      You're trying to read an integer of maximum length 10\,000 digits. That's far greater than the 2^{31}-1 max value of an int.

      • 1
        Sealeome1  commented on Aug. 1, 2021, 6:18 p.m.

        oh. I didn't know that. Thank you!