How to Search a Binary Tree in Java
The challenge
Given a sorted (in ascending order) integer array nums of n elements and a target value, write a function to search target in nums. If …
Technical Articles
In-depth guides, insights, and best practices for modern software engineering
How to Rotate a Singly Linked List in Java
The challenge
Given a linked list, rotate the list to the right by k places, where k is non-negative.
Example 1:
Input: 1->2->3->4->5->NULL, k = 2 …Read Article →
How to Insert into a Binary Search Tree using Java
The challenge
You are given the root node of a binary search tree (BST) and a value to insert into the tree. Return the root node of the BST after the …
Find the Complement of Base 10 Integer in Java
The challenge
Every non-negative integer N has a binary representation. For example, 5 can be represented as "101" in binary, 11 as …
Solve the Number of Recent Calls Challenge in Java
The challenge
You have a RecentCounter class which counts the number of recent requests within a certain time frame.
Implement the RecentCounter …
How to Calculate the Summation of a Number in Java
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 than 0.
For …
Read Article →How to Calculate all Unique Combinations of a Target using Backtracking 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 …
Who is going to pay for the wall? in Python
The challenge
Don Drumphet lives in a nice neighborhood, but one of his neighbors has started to let his house go. Don Drumphet wants to build a wall …
Read Article →Calculate the Total Amount of Points using Java
The challenge
Our football team finished the championship. The result of each match look like “x:y”. Results of all matches are recorded …
Read Article →Calculate the biggest of 3 numbers using Java
The challenge
Task
- Given three integers
a,b,c, return the largest number obtained after inserting the following operators and brackets:+,*,() - In …
Find the missing element between two arrays in Python
The challenge
Given two integer arrays where the second array is a shuffled duplicate of the first array with one element missing, find the missing …
Read Article →How to Count an Array of Boolean Values in 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 sheep …
Read Article →How to Solve the Car Pooling Challenge 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 …
How to Repeat a String in Java
The challenge
Write a function called repeat_str which repeats the given string src exactly count times.
repeatStr(6, "I") // "IIIIII" …How to Find the Smallest Integer in the Array 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 …
How to Count Odd Numbers Below N using Java
The challenge
Given a number n, return the number of positive odd numbers below n, EASY!
oddCount(7) //=> 3, i.e [1, 3, 5]
oddCount(15) //=> 7, …How to get the Length of the Last Word in a String 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 …
How to Convert a Number to Reversed Array of Digits in 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
import …How to Solve Unique Paths III in Java
The challenge
On a 2-dimensional grid, there are 4 types of squares:
1represents the starting square. There is exactly one starting square.2 …
How to Find the Mean/Average of a List of Numbers 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 all of the numbers together …
Read Article →How to Calculate BMI 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 as the body mass divided …
How to Solve the Robot Bounded In Circle Challenge 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: …
How to Convert a String to a Number 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, all …
Read Article →How to Convert an Integer to Binary using Java
The challenge
Given a non-negative integer n, write a function toBinary/ToBinary which returns that number in a binary format.
to_binary(1) /* should …