[C#][LeetCode][Easy] 258. Add Digits

心得:

題目要求將每一位數相加,直到剩下個位數。

問題:

Given a non-negative integer num, repeatedly add all its digits until the result has only one digit.

For example:

Given num = 38, the process is like: 3 + 8 = 11, 1 + 1 = 2. Since 2 has only one digit, return it.

答案:

  1. For + 遞迴
  2. LinQ + 遞迴
  3. Normal