솜씨좋은장씨

Given a non-negative integer num, repeatedly add all its digits until the result has only one digit. Example: Input: 38 Output: 2 Explanation: The process is like: 3 + 8 = 11, 1 + 1 = 2. Since 2 has only one digit, return it. Follow up: Could you do it without any loop/recursion in O(1) runtime? Solution class Solution: def addDigits(self, num: int) -> int: while True: if num // 10 < 1: return n..