LeetCode 0258. Add Digits Solution in Java, Python, C++, JavaScript, Go & Rust | Explanation + Code

Description

Given an integer num, repeatedly add all its digits until the result has only one digit, and return it.

 

Example 1:

Input: num = 38
Output: 2
Explanation: The process is
38 --> 3 + 8 --> 11
11 --> 1 + 1 --> 2 
Since 2 has only one digit, return it.

Example 2:

Input: num = 0
Output: 0

 

Constraints:

• 0 <= num <= 231 - 1

 

Follow up: Could you do it without any loop/recursion in O(1) runtime?

Solutions

Solution 1

PythonJavaC++GoRust

class Solution: def addDigits(self, num: int) -> int: return 0 if num == 0 else (num - 1) % 9 + 1(code-box)

class Solution { public int addDigits(int num) { return (num - 1) % 9 + 1; } }(code-box)

class Solution { public: int addDigits(int num) { return (num - 1) % 9 + 1; } };(code-box)

func addDigits(num int) int { if num == 0 { return 0 } return (num-1)%9 + 1 }(code-box)

impl Solution { pub fn add_digits(mut num: i32) -> i32 { ((num - 1) % 9) + 1 } }(code-box)