Get the Sum of Digits / Digital Root using Java
The challenge
Digital root is the recursive sum of all the digits in a number.
Given n, take the sum of the digits of n. If that value has more than …
Technical Articles
In-depth guides, insights, and best practices for modern software engineering
How to write a Chain Adding Function in Python
The challenge
We want to create a function that will add numbers together when called in succession.
add(1)(2);
# returns 3
We also want to be able to …
Read Article →Get the next biggest number with the same digits using Python
The challenge
Create a function that takes a positive integer and returns the next bigger number that can be formed by rearranging its digits. For …
Read Article →Solving Tribonacci Sequence with Python
The challenge
As the name may already reveal, it works basically like a Fibonacci, but summing the last 3 (instead of 2) numbers of the sequence to …
Read Article →The Casino Chips Problem Solved with Python
The challenge
You are given three piles of casino chips: white, green and black chips:
- the first pile contains only white chips
- the second pile …
Check if Isogram using Python
The challenge
An isogram is a word that has no repeating letters, consecutive or non-consecutive. Implement a function that determines whether a …
Read Article →Find the Longest Common Prefix using Python
The challenge
Write a function to find the longest common prefix string amongst an array of strings. This string manipulation challenge requires …
Read Article →Count and Say with Python
The challenge
he count-and-say sequence is the sequence of integers with the first five terms as following:
1 is read off as "one 1" or 11 …
The Plus One problem solved with Python
The challenge
Given a non-empty array of digits representing a non-negative integer, increment one to the integer. This challenge involves array …
Read Article →Solving the Single Number problem in Python
The challenge
Given a non-empty array of integers, every element appears twice except for one. Find that single one.
Note:
Your algorithm should have …
Read Article →Rotate a Matrix List in Python
The challenge
You are given an n x n 2D matrix representing an image.
Rotate the image by 90 degrees (clockwise).
Note:
You have to rotate the image …
Read Article →Check if Valid Sudoku Blocks in Java
The challenge of solving valid Sudoku blocks
Determine if a 9×9 Sudoku board is valid. Only the filled cells need to be validated according to the …
Read Article →