The challenge Write a program that finds the summation of every number from 1 to num. The number will always be a positive integer greater… Read More »How to Calculate the Summation of a Number in Java

The challenge Given an array of distinct integers candidates and a target integer target, return a list of all unique combinations of candidates where the chosen numbers sum to target. You may return the combinations in any order.… Read More »How to Calculate all Unique Combinations of a Target using Backtracking in Java

The challenge Task Given three integers a ,b ,c, return the largest number obtained after inserting the following operators and brackets: +, *, () In other words , try every combination of a,b,c with [*+()] , and… Read More »Calculate the biggest of 3 numbers using Java

The challenge Consider an array/list of sheep where some sheep may be missing from their place. We need a function that counts the number of… Read More »How to Count an Array of Boolean Values in Java

The challenge You are driving a vehicle that has capacity empty seats initially available for passengers.  The vehicle only drives east (ie. it cannot turn around and drive west.) Given a list… Read More »How to Solve the Car Pooling Challenge in Java

The challenge Write a function called repeat_str which repeats the given string src exactly count times. The solution in Java Java comes with a built-in on the String class. Called repeat,… Read More »How to Repeat a String in Java

The challenge Given an array of integers your solution should find the smallest integer. For example: Given [34, 15, 88, 2] your solution will return 2 Given [34, -345,… Read More »How to Find the Smallest Integer in the Array in Java

The challenge Given a number n, return the number of positive odd numbers below n, EASY! Expect large Inputs! Test cases The solution in Java At first… Read More »How to Count Odd Numbers Below N using Java

The challenge Given a string s consists of upper/lower-case alphabets and empty space characters ‘ ‘, return the length of last word (last word means the last appearing… Read More »How to get the Length of the Last Word in a String using Java

The challenge Given a random non-negative number, you have to return the digits of this number within an array in reverse order. Test cases Solution… Read More »How to Convert a Number to Reversed Array of Digits in Java

The challenge On a 2-dimensional grid, there are 4 types of squares: 1 represents the starting square.  There is exactly one starting square. 2 represents the ending square. … Read More »How to Solve Unique Paths III in Java

The challenge Find the mean (average) of a list of numbers in an array. To find the mean (average) of a set of numbers add… Read More »How to Find the Mean/Average of a List of Numbers in Java

The challenge BMI stands for Body Mass Index and is a value derived from the mass and height of a person. The BMI is defined… Read More »How to Calculate BMI in Java

The challenge On an infinite plane, a robot initially stands at (0, 0) and faces north.  The robot can receive one of three instructions: “G”: go straight 1 unit;… Read More »How to Solve the Robot Bounded In Circle Challenge in Java

The challenge We need a function that can transform a string into a number. What ways of achieving this do you know? Note: Don’t worry,… Read More »How to Convert a String to a Number in Java

The challenge Given a non-negative integer n, write a function toBinary/ToBinary which returns that number in a binary format. Test cases The solution in Java Alternative 1: Alternative… Read More »How to Convert an Integer to Binary using Java

Exclusive “or” (xor) Logical Operator In some scripting languages like PHP, there exists a logical operator (e.g. &&, ||, and, or, etc.) called the “Exclusive Or” (hence the name… Read More »How to create a Logical Operator in Java

The challenge Write a function that merges two sorted arrays into a single one. The arrays only contain integers. Also, the final outcome must be… Read More »How to merge sorted integer arrays (without duplicates) in Java

The challenge Your job is to find the gravitational force between two spherical objects (obj1 , obj2). Two arrays are give : arr_val (value array),… Read More »Find the Force of Gravity Between Two Objects with Java

The challenge You are playing the following Bulls and Cows game with your friend: You write down a number and ask your friend to guess what the… Read More »Playing the Bulls and Cows Game in Java

The challenge Given a binary tree, each node has value 0 or 1.  Each root-to-leaf path represents a binary number starting with the most significant bit.  For example,… Read More »Calculate the Sum of Root To Leaf Binary Numbers in Java