# Algorithms 101: Product and Sum of Digits in JavaScript

## Noob v. Algorithms #24, Parsing digits is a lot faster when you avoid using strings!

Today’s challenge in LeetCode is Subtract the Product and Sum of the Digits of an Integer.

# Algorithms 101: Find the Difference between Two Arrays in JavaScript

## Noob. v. Algorithms #23, a custom, speedy method for finding the difference in two arrays

Today’s challenge from LeetCode is Find All Disappeared Numbers in Array.

# Algorithms 101: Rotate Array in JavaScript — three solutions

## Noob v. Algorithms #22, playing with .pop(), .unshift() and .splice()

Browsing through the top interview questions in LeetCode, one of the harder easy questions is this one:

# Algorithms 101: includes() vs. indexOf() in JavaScript

## Noob v. Algorithms #21: Intersection of Two Arrays, with .filter()

In today’s challenge from LeetCode, we’re looking for the common items in two arrays.

# Algorithms 101: Container with most water in JavaScript

## Noob v. Algorithms # 20, iterating from the outside in

If you’re a noob like me you may dread the ‘medium’ level algorithms on LeetCode. As it turns out, a few of them are actually easier than the so-called Easy ones. Here’s a gentle introduction to the medium level.

Today’s challenge from Leetcode is to choose the container that holds the most water:

# Algorithms 101: Level Patio in JavaScript

## Noob v. Algorithms #19, improving runtime by operating on arrays in place

Long ago, my husband and I hand-laid a brick patio in our backyard. (Yes, we put in a by-the-book base of gravel, sand, weed-blocking material, you name it). Over the years, some areas have sunk. If we wanted to redo it, we’d have to take off the bricks and level the gravel base underneath.

Which brings us to our challenge:

Let’s say you the following (lumpy!) patio, where each number stands for the height of the gravel in that part of the grid, measured in arbitrary units:

`8    4    3    9    21    5    6    8    07    4    3    9…`

# Algorithms 101: Group Anagrams in JavaScript

## Noob v. Algorithms #18: fun with hashes

A few days ago, I came across this challenge from LeetCode:

# React: Try FadeIn + Redirect = cool transitions

## Plus: how to hide fun stuff behind slow fade-ins …

A few months ago, I created a React App portfolio website. I gave it a few pages:

• Home
• Projects
• Resume
• Blog Posts

On the home page, I added some basic welcome text, a large photo and a link to my portfolio page. Then I began to wonder: why force visitors to enter through the home page, when the page I really want them to see is the portfolio page?

I considered dumping the home page altogether, but it is kind of nice to have somewhere to start.

So how can you have a lovely home page without making visitors feel like it’s an unnecessary pit stop on the way to a more popular page? …

# Algorithms 101: Count Primes in JavaScript

Noob v. Algorithms #17, the Sieve of Eratosthenes

Before we get started on today’s challenge, a word about prime numbers: They are, of course, numbers that are greater than one that are divisible only by themselves and one.

If you’re like me, you probably learned about them many times by the time you graduated from high school. But you missed the memo on why we care. The short answer is, we can use very large prime numbers for encryption. More details on that here.

For today’s puzzle in LeetCode:

# Algorithms 101: Find Pairs in JavaScript

Noob v. Algorithms #16, frequency counters and Set

Today’s challenge on LeetCode: