Java

Sum by Factors in Java

January 26, 2021 #Java

The challenge

Given an array of positive or negative integers

I= [i<sub>1</sub>,..,i<sub>n</sub>]

you have to produce a sorted …

Count the divisors of a number in Java

January 25, 2021 #Java

The challenge

Count the number of divisors of a positive integer n.

Random tests go up to n = 500000.

Examples

numberOfDivisors(4)  == 3 // 1, 2, 4 …

My smallest code interpreter in Java

January 24, 2021 #Java

The challenge

Inspired from real-world Brainf**k, we want to create an interpreter of that language which will support the following instructions: …

Pick peaks in Java

January 23, 2021 #Java

The challenge

Write a function that returns the positions and the values of the “peaks” (or local maxima) of a numeric array.

For example, …

Number of trailing zeros of N in Java

January 22, 2021 #Java

The challenge

Write a program that will calculate the number of trailing zeros in a factorial of a given number.

N! = 1 * 2 * 3 * ... * N

Be careful …

Alphabetic Anagrams in Java

January 21, 2021 #Java

The challenge

Consider a “word” as any sequence of capital letters A-Z (not limited to just “dictionary words”). For any word …

Remove file from Git without deleting locally

January 20, 2021 #Java

If you find yourself in a position where you have already committed some files to git, and they are in the remote repository already, but you want to …

Recover a secret string from random triplets in Java

January 19, 2021 #Java

The challenge

There is a secret string which is unknown to you. Given a collection of random triplets from the string, recover the original string.

A …

Range Extraction in Java

January 18, 2021 #Java

The challenge

A format for expressing an ordered list of integers is to use a comma separated list of either

• individual integers
• or a range of …

Reversed Words in Java

January 17, 2021 #Java

The challenge

Complete the solution so that it reverses all of the words within the string passed in.

Example:

ReverseWords.reverseWords("The …

CamelCase Method in Java

January 16, 2021 #Java

The challenge

Write a simple CamelCase method for strings.

All words must have their first letter capitalized without spaces.

Example:

// …

Even or Odd in Java

January 15, 2021 #Java

The challenge

Create a function that takes an integer as an argument and returns “Even” for even numbers or “Odd” for odd …

Square Every Digit in Java

January 14, 2021 #Java

The challenge

You need to square every digit of a number and concatenate them.

For example, if we run 9119 through the function, 811181 will come out, …

Simple number sequence in Java

January 13, 2021 #Java

The challenge

You are given a string of numbers in sequence and your task will be to return the missing number. If there is no number missing or there …

Roman Numerals Encoder in Java

January 12, 2021 #Java

The challenge

Create a function taking a positive integer as its parameter and returning a string containing the Roman Numeral representation of that …

First Variation on Caesar Cipher in Java

January 11, 2021 #Java

The challenge

The action of a Caesar cipher is to replace each plaintext letter (plaintext letters are from ‘a’ to ‘z’ or from ‘A’ …

Century From Year in Java

January 10, 2021 #Java

The challenge

The first century spans from the year 1 up to and including the year 100, The second – from the year 101 up to and including the year …

Find the Smallest Number in Java

January 9, 2021 #Java

The challenge

You have a positive number n consisting of digits. You can do at most one operation: Choosing the index of a digit in the number, remove …

Convert Array to Tree in Java

January 8, 2021 #Java

The challenge

You are given a non-null array of integers. Implement the method arrayToTree which creates a binary tree from its values in accordance …

Common Denominators in Java

January 7, 2021 #Java

The challenge

You will have a list of rationals in the form

{ {numer_1, denom_1} , ... {numer_n, denom_n} } 
or
[ [numer_1, denom_1] , ... [numer_n, …

Primes in Numbers in Java

January 6, 2021 #Java

The challenge

Given a positive number n > 1 find the prime factor decomposition of n. The result will be a string with the following form : …

Maximum subarray sum in Java

January 5, 2021 #Java

The challenge

The maximum sum subarray problem consists in finding the maximum sum of a contiguous subsequence in an array or list of integers: …

Validate Credit Card Number in Java

January 4, 2021 #Java

The challenge

Let’s implement the Luhn Algorithm, which is used to help validate credit card numbers.

Given a positive integer of up to 16 …

Find the unique number using Java

January 3, 2021 #Java

The challenge

There is an array with some numbers. All numbers are equal except for one. Try to find it!

Solution.findUniq(new double[]{ 1, 1, 1, 2, …