Java makes it easy to convert a string to an array by providing the built-in .split() method on the String object. The challenge Write a… Read More »How to Convert a String to an Array in Java

The challenge Create a function that will return a string that combines all of the letters of the three inputed strings in groups. Taking the… Read More »How to Loop and Combine Three Strings in Java

The challenge The medians of a triangle are the segments that unit the vertices with the midpoint of their opposite sides. The three medians of… Read More »How to Localize The Barycenter of a Triangle in Java

The challenge Given the coordinates of four points in 2D space p1, p2, p3 and p4, return true if the four points construct a square. The coordinate of a point pi is represented as [xi, yi].… Read More »How to Calculate a Valid Square in Java

The challenge Everybody knows the classic “half your age plus seven” dating rule that a lot of people follow (including myself). It’s the ‘recommended’ age range in… Read More »How to Calculate Age Range Compatibility as an Equation in Java

The challenge Let’s call any (contiguous) subarray B (of A) a mountain if the following properties hold: B.length >= 3 There exists some 0 < i < B.length – 1 such… Read More »How to Find the Longest Mountain in Array in Java

The challenge Given an encoded string, return its decoded string. The encoding rule is: k[encoded_string], where the encoded_string inside the square brackets is being repeated exactly k times. Note that k is… Read More »How to Solve the “Decode a String” Challenge in Java

The challenge Given the root of a binary tree, find the maximum value V for which there exist different nodes A and B where V = |A.val – B.val| and A is an ancestor of B. A node A is an ancestor… Read More »How to Find the Maximum Difference Between Node and Ancestor in Java

The challenge Create a function that finds the integral of the expression passed. In order to find the integral all you need to do is add one… Read More »How to Find the Integral using Java

The challenge Write a function stringy that takes a size and returns a string of alternating ‘1s’ and ‘0s’. The string should start with a 1. A string with size 6 should return :’101010′. With size 4 should return… Read More »How to Build Strings from a Size in Java

The challenge Say you have an array for which the ith element is the price of a given stock on day i. If you were only permitted to… Read More »Best Time to Buy and Sell Stock in Java

The challenge Write a method, that will get an integer array as parameter and will process every number from this array.Return a new array with… Read More »How to Solve the “To square(root) or not to square(root)” Challenge in Java

The challenge “A divisibility rule is a shorthand way of determining whether a given integer is divisible by a fixed divisor without performing the division,… Read More »Solving the Rule of Divisibility by 13 in Java

The challenge Given two strings A and B of lowercase letters, return true if you can swap two letters in A so the result is equal to B, otherwise, return false. Swapping letters is defined… Read More »How to Calculate Buddy Strings in Java

The challenge Given a binary matrix A, we want to flip the image horizontally, then invert it, and return the resulting image. To flip an image… Read More »How to Flip a Binary Matrix in Java

The challenge Given the root of a binary tree, return the sum of every tree node’s tilt. The tilt of a tree node is the absolute difference between the sum of all left… Read More »How to Tilt a Binary Tree 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, the only… Read More »How to solve the House Robber Challenge in Java

The challenge You have an initial power of P, an initial score of 0, and a bag of tokens where tokens[i] is the value of the ith token (0-indexed). Your goal is to maximize your total score by potentially… Read More »How to Solve the Bag of Tokens Challenge in Java

The challenge Given an array of integers nums and an integer threshold, we will choose a positive integer divisor and divide all the array by it and sum the result… Read More »How to Find the Smallest Divisor Given a Threshold in Java

The challenge You will be given a vector of strings. You must sort it alphabetically (case-sensitive, and based on the ASCII values of the chars)… Read More »How to Sort and Star a String Array in Java

The challenge Given a string s, the power of the string is the maximum length of a non-empty substring that contains only one unique character. Return the power of… Read More »How to Count Consecutive Characters in Java

The challenge Write a function to convert a name into initials. This challenge strictly takes two words with one space in between them. The output… Read More »How to Abbreviate a Two Word Name in Java

The challenge Sort a linked list using insertion sort. A graphical example of insertion sort. The partially sorted list (black) initially contains only the first… Read More »How to Sort a Linked List using Insertion Sort in Java