Sum of Digits Using Recursion

Problem

Calculate the sum of decimal digits in a nonnegative integer.

Examples

Example 1

Input: 12345

Output: 15

Example 2

Input: 0

Output: 0

Input and output use JSON-compatible values. For linked-list and tree questions, arrays represent the node structure as described above. Your code should implement solve(input).

Write your solutionImplement solve(input). Your draft is saved in this browser.

Compiler

How to solve Sum of Digits Using Recursion

Calculate the sum of decimal digits in a nonnegative integer. Separate the last digit using modulo 10. The reference implementation illustrates this approach; check the example and edge cases.

Time and space complexity

O(d) time and O(d) recursion depth where d is the number of digits.

Practise and improve

Choose JavaScript, TypeScript or Python, complete the starter code, then select Run Tests. Request a hint when you need guidance, or choose View solution and confirm if you would like to study the reference implementation.