Java

Simple string expansion in Java

March 2, 2021 #Java

The challenge

Consider the following expansion:

// because "ab" repeats 3 times
solve("3(ab)") == "ababab"

// because …

Hamming Numbers in Java

March 1, 2021 #Java

The challenge

A Hamming number is a positive integer of the form 2i3j5k, for some non-negative integers i, j, and k.

Block sequence in Java

February 28, 2021 #Java

The challenge

Consider the following array:

[1, 12, 123, 1234, 12345, 123456, 1234567, 12345678, 123456789, 12345678910, 1234567891011...]

If we join …

Roman Numerals Helper in Java

February 27, 2021 #Java

The challenge

Create a RomanNumerals class that can convert a roman numeral to and from an integer value. It should follow the API demonstrated in the …

Closest pair of points in linearithmic time in Java

February 26, 2021 #Java

The challenge

Given a number of points on a plane, your task is to find two points with the smallest distance between them in linearithmic O(n log n) …

Find sum of top-left to bottom-right diagonals in Java

February 25, 2021 #Java

The challenge

Given a square matrix (i.e. an array of subarrays), find the sum of values from the first value of the first array, the second value of …

Sweeping trees in Java

February 24, 2021 #Java

The challenge

You will be given a list of strings representing nodes in a rooted tree. A visual representation of a very simple rooted tree could be: …

Detect Pangram in Java

February 23, 2021 #Java

The challenge

A pangram is a sentence that contains every single letter of the alphabet at least once. For example, the sentence “The quick …

Remove the parentheses in Java

February 22, 2021 #Java

The challenge

In this challenge you are given a string for example:

"example(unwanted thing)example"

Your task is to remove everything inside …

What century is it in Java

February 21, 2021 #Java

The challenge

Return the century of the input year. The input will always be a 4 digit string, so there is no need for validation.

Examples …

Lost number in number sequence in Java

February 20, 2021 #Java

The challenge

An ordered sequence of numbers from 1 to N is given. One number might have deleted from it, then the remaining numbers were mixed. Find …

Simple string reversal in Java

February 19, 2021 #Java

The challenge

In this challenge, we are going to reverse a string while maintaining the spaces (if any) in their original place.

For example: …