How to Remove First and Last Character in a String in Java
The challenge
The goal is to create a function that removes the first and last characters of a string. You don’t have to worry with strings with …
Read Article →Technical Articles
In-depth guides, insights, and best practices for modern software engineering
How to Distribute Halloween Candies by Rating Value in Java
The challenge
There are N children standing in a line. Each child is assigned a rating value.
You are giving candies to these children subjected to …
Read Article →How to Distribute Halloween Candies in Java
The challenge
You have n candies, the i<sup>th</sup> candy is of type candies[i].
You want to distribute the candies equally between a …
Read Article →How to Solve the Maximize Distance to Closest Person Challenge in Java
The challenge
You are given an array representing a row of seats where seats[i] = 1 represents a person sitting in the i<sup>th</sup> …
How to Get Character from ASCII Value in Java
The challenge
Write a function which takes a number and returns the corresponding ASCII char for that value.
Example:
Ascii.getChar(65) // => …Finding a Needle in a Haystack in Java
The challenge
Can you find the needle in the haystack?
Write a function findNeedle() that takes an array full of junk but containing one …
How to Solve the Champagne Tower in Java
The challenge
We stack glasses in a pyramid, where the first row has 1 glass, the second row has 2 glasses, and so on until the 100th row. Each glass …
How to Solve the 132 Pattern in Java
The challenge
Given an array of n integers nums, a 132 pattern is a subsequence of three integers nums[i], nums[j] and nums[k] such that i < j < …
How to Replace all Vowels in a String in Java
The challenge
Replace all vowel to exclamation mark in the sentence. aeiouAEIOU is vowel.
Examples
replace("Hi!") === "H!!" …How to Get the N-th Power in Java
The challenge
You are given an array with positive numbers and a number N. You should find the N-th power of the element in the array with the index …
Read Article →How to Count the Minimum Depth of a Binary Tree in Java
The challenge
Given a binary tree, find its minimum depth.
The minimum depth is the number of nodes along the shortest path from the root node down to …
Read Article →How to Solve the House Robber II Challenge in Java
The challenge
You are a professional robber planning to rob houses along a street. Each house has a certain amount of money stashed. All houses at …
Read Article →How to Clone a Graph in Java
The challenge
Given a reference of a node in a connected undirected graph.
Return a deep copy (clone) of the graph. Effectively a graph copy.
Each …
Read Article →How to Return Random Values in Java
The challenge
Ghost objects are instantiated without any arguments.
Ghost objects are given a random color attribute of white" or …
Read Article →How to Compare Version Numbers in Java
The challenge
Compare two version numbers version1 and version2.
If <em>version1</em> > <em>version2</em> …
How to Return the First N Elements in Java
The challenge
Create a method take that accepts a list/array and a number n, and returns a list/array array of the first n elements from the …
Read Article →How to Search a 2d Matrix/Array in Java
The challenge
Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties:
- Integers in each …
Calculate the Surface Area and Volume of a Box with Java
The challenge
Write a function that returns the total surface area and volume of a box as an array: [area, volume]
The solution in Java
We know that …
Read Article →Find Numbers which are Divisible by given Number in Java
The challenge
Complete the function which takes two arguments and returns all numbers which are divisible by the given divisor. First argument is an …
Read Article →How to Split a Subdirectory to a New Git Repository and Keep the History
There comes a time when you need to split out a subdirectory into it’s own git repo.
This is a very simple task if you don’t care about …
Read Article →Get the Maximum XOR of Two Numbers in an Array in Java
The challenge
Given a non-empty array of numbers, a, a1, a2, … , an-1, where 0 ≤ ai < 231.
Find the maximum result of ai XOR aj, where 0 ≤ i, j …
Read Article →How to Get the Opposite of a Number in Java
The challenge
Given a number, find its opposite.
Examples:
1: -1
14: -14
-34: 34
The solution in Java
We return the number itself multiplied by a …
Read Article →How to Find the Area or Perimeter of a 4-sided Polygon using Java
The challenge
You are given the length and width of a 4-sided polygon. The polygon can either be a rectangle or a square.
If it is a square, return …
How to Parse Int from Char in Java
The challenge
We take in a String where the first place contains a number, write a function that takes in this String and returns an int containing …