Objective

Welcome to Day 18! Today we’re learning about Stacks and Queues. Check out the Tutorial tab for learning materials and an instructional video!

A palindrome is a word, phrase, number, or other sequence of characters which reads the same backwards and forwards. Can you determine if a given string, s, is a palindrome?

To solve this challenge, we must first take each character in s, enqueue it in a queue, and also push that same character onto a stack. Once that’s done, we must dequeue the first character from the queue and pop the top character off the stack, then compare the two characters to see if they are the same; as long as the characters match, we continue dequeueing, popping, and comparing each character until our containers are empty (a non-match means s isn’t a palindrome).

Write the following declarations and implementations:

1. Two instance variables: one for your stack, and one for your queue.
2. A void pushCharacter(char ch) method that pushes a character onto a stack.
3. A void enqueueCharacter(char ch) method that enqueues a character in the queue instance variable.
4. A char popCharacter() method that pops and returns the character at the top of the stack instance variable.
5. A char dequeueCharacter() method that dequeues and returns the first character in the queue instance variable.

Objective

Yesterday’s challenge taught you to manage exceptional situations by using try and catch blocks. In today’s challenge, you’re going to practice throwing and propagating an exception. Check out the Tutorial tab for learning materials and an instructional video!

Objective

Today, we’re getting started with Exceptions by learning how to parse an integer from a string and print a custom error message. Check out the Tutorial tab for learning materials and an instructional video!

Objective

Today we’re working with Linked Lists. Check out the Tutorial tab for learning materials and an instructional video!

A Node class is provided for you in the editor. A Node object has an integer data field, data, and a Node instance pointer, next, pointing to another node (i.e.: the next node in a list).

A Node insert function is also declared in your editor. It has two parameters: a pointer, head, pointing to the first node of a linked list, and an integer data value that must be added to the end of the list as a new Node object.

Objective

Today we’re discussing scope. Check out the Tutorial tab for learning materials and an instructional video!

The absolute difference between two integers, a and b, is written as |a - b|. The maximum absolute difference between two integers in a set of positive integers, elements, is the largest absolute difference between any two integers in elements.

The Difference class is started for you in the editor. It has a private integer array (elements) for storing N non-negative integers, and a public integer (maximumDifference) for storing the maximum absolute difference.

Objective

Today, we’re taking what we learned yesterday about Inheritance and extending it to Abstract Classes. Because this is a very specific Object-Oriented concept, submissions are limited to the few languages that use this construct. Check out the Tutorial tab for learning materials and an instructional video!

Objective

Today, we’re delving into Inheritance. Check out the attached tutorial for learning materials and an instructional video!

Objective

Today, we’re building on our knowledge of Arrays by adding another dimension. Check out the Tutorial tab for learning materials and an instructional video!

Objective

Today, we’re working with binary numbers. Check out the Tutorial tab for learning materials and an instructional video!

Task

Given a base-10 integer, n, convert it to binary (base-2). Then find and print the base-10 integer denoting the maximum number of consecutive 1‘s in n‘s binary representation.

Objective

Today, we’re learning and practicing an algorithmic concept called Recursion. Check out the Tutorial tab for learning materials and an instructional video!

Recursive Method for Calculating Factorial