After a decade in large tech, I know how software engineers were interviewed. I've seen outstanding engineers fail interviews because their responses were too vague.

So I wrote Nail A Coding Interview: Six-Step Mental Framework. Give candidates a mental framework for coding questions; help organizations better prepare candidates so they can calibrate traits.

Recently, I sold more than 100 books, something I never expected.

In this essay, I'll describe my publication journey, which included self-doubt and little triumphs. I hope this helps if you want to publish.

It was originally a Medium post.

How did I know to develop a coding interview book? Years ago, I posted on Medium.

Six steps to ace a coding interview Inhale. blog.devgenius.io

This story got a lot of attention and still gets a lot of daily traffic. It indicates this domain's value.

Converted the Medium article into an ebook

The Medium post contains strong bullet points, but it is missing the “flesh”. How to use these strategies in coding interviews, for example. I filled in the blanks and made a book.

I made the book cover for free. It's tidy.

Shared the article with my close friends on my social network WeChat.

I shared the book on Wechat's Friend Circle (朋友圈) after publishing it on Gumroad. Many friends enjoyed my post. It definitely triggered endorphins.

In Friend Circle, I presented a 100% off voucher. No one downloaded the book. Endorphins made my heart sink.

Several days later, my Apple Watch received a Gumroad notification. A friend downloaded it. I majored in finance, he subsequently said. My brother-in-law can get it? He downloaded it to cheer me up.

I liked him, but was disappointed that he didn't read it.

The Tipping Point: Reddit's Free Giving

I trusted the book. It's based on years of interviewing. I felt it might help job-hunting college students. If nobody wants it, it can still have value.

I posted the book's link on /r/leetcode. I told them to DM me for a free promo code.

Momentum shifted everything. Gumroad notifications kept coming when I was out with family. Following orders.

As promised, I sent DMs a promo code. Some consumers ordered without asking for a promo code. Some readers finished the book and posted reviews.

My book was finally on track.

A 5-Star Review, plus More

A reader afterwards DMed me and inquired if I had another book on system design interviewing. I said that was a good idea, but I didn't have one. If you write one, I'll be your first reader.

Later, I asked for a book review. Yes, but how? That's when I learned readers' reviews weren't easy. I built up an email pipeline to solicit customer reviews. Since then, I've gained credibility through ratings.

Learnings

I wouldn't have gotten 100 if I gave up when none of my pals downloaded. Here are some lessons.

• Your friends are your allies, but they are not your clients.

• Be present where your clients are

• Request ratings and testimonials

• gain credibility gradually

I did it, so can you. Follow me on Twitter @imgracehuang for my publishing and entrepreneurship adventure.

I joined the 1000 Digital Startups Movement (Gerakan 1000 Startup Digital) in 2017 and learned a lot about the startup sector. My previous essay outlined what a startup is and what must be prepared. Here I'll offer raw ideas for better products.

Intro

A good startup solves a problem. These can include environmental, economic, energy, transportation, logistics, maritime, forestry, livestock, education, tourism, legal, arts and culture, communication, and information challenges. Everything I wrote is simply a basic idea (as inspiration) and requires more mapping and validation. Learn how to construct a startup to maximize launch success.

Adrian Gunadi (Investree Co-Founder) taught me that a Founder or Co-Founder must be willing to be CEO (Chief Everything Officer). Everything is independent, including drafting a proposal, managing finances, and scheduling appointments. The best individuals will come to you if you're the best. It's easier than consulting Andy Zain (Kejora Capital Founder).

Description

To help better understanding from your idea, try to answer this following questions:

- Describe your idea/application
Maximum 1000 characters.

- Background
Explain the reasons that prompted you to realize the idea/application.

- Objective
Explain the expected goals of the creation of the idea/application.

- Solution
A solution that tells your idea can be the right solution for the problem at hand.

- Uniqueness
What makes your idea/app unique?

- Market share
Who are the people who need and are looking for your idea?

- Marketing Ways and Business Models
What is the best way to sell your idea and what is the business model?

Not everything here is a startup idea. It's meant to inspire creativity and new perspectives.

Ideas

#Application

1. Medical students can operate on patients or not. Applications that train prospective doctors to distinguish body organs and their placement are useful. In the advanced stage, the app can be built with numerous approaches so future doctors can practice operating on patients based on their ailments. If they made a mistake, they'd start over. Future doctors will be more assured and make fewer mistakes this way.

2. VR (virtual reality) technology lets people see 3D space from afar. Later, similar technology was utilized to digitally sell properties, so buyers could see the inside and room contents. Every gadget has flaws. It's like a gold mine for robbers. VR can let prospective students see a campus's facilities. This facility can also help hotels promote their products.

3. How can retail entrepreneurs maximize sales? Most popular goods' sales data. By using product and brand/type sales figures, entrepreneurs can avoid overstocking. Walmart computerized their procedures to track products from the manufacturer to the store. As Retail Link products sell out, suppliers can immediately step in.

4. Failing to marry is something to be avoided. But if it had to happen, the loss would be like the proverb “rub salt into the wound”.  On the I do Now I dont website, Americans who don't marry can resell their jewelry to other brides-to-be. If some want to cancel the wedding and receive their down money and dress back, others want a wedding with particular criteria, such as a quick date and the expected building. Create a DP takeover marketplace for both sides.

#Games

1. Like in the movie, players must exit the maze they enter within 3 minutes or the shape will change, requiring them to change their strategy. The maze's transformation time will shorten after a few stages.

2. Treasure hunts involve following clues to uncover hidden goods. Here, numerous sponsors are combined in one boat, and participants can choose a game based on the prizes. Let's say X-mart is a sponsor and provides riddles or puzzles to uncover the prize in their store. After gathering enough points, the player can trade them for a gift utilizing GPS and AR (augmented reality). Players can collaborate to increase their chances of success.

3. Where's Wally? Where’s Wally displays a thick image with several things and various Wally-like characters. We must find the actual Wally, his companions, and the desired object. Make a game with a map where players must find objects for the next level. The player must find 5 artifacts randomly placed in an Egyptian-style mansion, for example. In the room, there are standard tickets, pass tickets, and gold tickets that can be removed for safekeeping, as well as a wall-mounted carpet that can be stored but not searched and turns out to be a flying rug that can be used to cross/jump to a different place. Regular tickets are spread out since they can buy life or stuff. At a higher level, a black ticket can lower your ordinary ticket. Objects can explode, scattering previously acquired stuff. If a player runs out of time, they can exchange a ticket for more.

#TVprogram

1. At the airport there are various visitors who come with different purposes. Asking tourists to live for 1 or 2 days in the city will be intriguing to witness.

2. Many professions exist. Carpenters, cooks, and lawyers must have known about job desks. Does HRD (Human Resource Development) only recruit new employees? Many don't know how to become a CEO, CMO, COO, CFO, or CTO. Showing young people what a Program Officer in an NGO does can help them choose a career.

#StampsCreations

Philatelists know that only the government can issue stamps. I hope stamps are creative so they have more worth.

1. Thermochromic pigments (leuco dyes) are well-known for their distinctive properties. By putting pigments to black and white batik stamps, for example, the black color will be translucent and display the basic color when touched (at a hot temperature).

2. In 2012, Liechtenstein Post published a laser-art Chinese zodiac stamp. Belgium (Bruges Market Square 2012), Taiwan (Swallow Tail Butterfly 2009), etc. Why not make a stencil of the president or king/queen?

3. Each country needs its unique identity, like Taiwan's silk and bamboo stamps. Create from your country's history. Using traditional paper like washi (Japan), hanji (Korea), and daluang/saeh (Indonesia) can introduce a country's culture.

4. Garbage has long been a problem. Bagasse, banana fronds, or corn husks can be used as stamp material.

5. Austria Post published a stamp containing meteor dust in 2006. 2004 meteorite found in Morocco produced the dust. Gibraltar's Rock of Gilbraltar appeared on stamps in 2002. What's so great about your country? East Java is muddy (Lapindo mud). Lapindo mud stamps will be popular. Red sand at Pink Beach, East Nusa Tenggara, could replace the mud.

#PostcardCreations

1. Map postcards are popular because they make searching easier. Combining laser-cut road map patterns with perforated 200-gram paper glued on 400-gram paper as a writing medium. Vision-impaired people can use laser-cut maps.

2. Regional art can be promoted by tucking traditional textiles into postcards.

3. A thin canvas or plain paper on the card's front allows the giver to be creative.

4. What is local crop residue? Cork lids, maize husks, and rice husks can be recycled into postcard materials.

5. Have you seen a dried-flower bookmark? Cover the postcard with mica and add dried flowers. If you're worried about losing the flowers, you can glue them or make a postcard envelope.

6. Wood may be ubiquitous; try a 0.2-mm copper plate engraved with an image and connected to a postcard as a writing medium.

7. Utilized paper pulp can be used to hold eggs, smartphones, and food. Form a smooth paper pulp on the plate with the desired image, the Golden Gate bridge, and paste it on your card.

8. Postcards can promote perfume. When customers rub their hands on the card with the perfume image, they'll smell the aroma.

#Tour #Travel

Tourism activities can be tailored to tourists' interests or needs. Each tourist benefits from tourism's distinct aim.

Let's define tourism's objective and purpose.

• Holiday Tour is a tour that its participants plan and do in order to relax, have fun, and amuse themselves.

• A familiarization tour is a journey designed to help travelers learn more about (survey) locales connected to their line of work.

• An educational tour is one that aims to give visitors knowledge of the field of work they are visiting or an overview of it.

• A scientific field is investigated and knowledge gained as the major goal of a scientific tour.

• A pilgrimage tour is one designed to engage in acts of worship.

• A special mission tour is one that has a specific goal, such a commerce mission or an artistic endeavor.

• A hunting tour is a destination for tourists that plans organized animal hunting that is only allowed by local authorities for entertainment purposes.

Every part of life has tourism potential. Activities include:

1. Those who desire to volunteer can benefit from the humanitarian theme and collaboration with NGOs. This activity's profit isn't huge but consider the environmental impact.

2. Want to escape the city? Meditation travel can help. Beautiful spots around the globe can help people forget their concerns. A certified yoga/meditation teacher can help travelers release bad energy.

3. Any prison visitors? Some prisons, like those for minors under 17, are open to visitors. This type of tourism helps mental convicts reach a brighter future.

4. Who has taken a factory tour/study tour? Outside-of-school study tour (for ordinary people who have finished their studies). Not everyone in school could tour industries, workplaces, or embassies to learn and be inspired. Shoyeido (an incense maker) and Royce (a chocolate maker) offer factory tours in Japan.

5. Develop educational tourism like astronomy and archaeology. Until now, only a few astronomy enthusiasts have promoted astronomy tourism. In Indonesia, archaeology activities focus on site preservation, and to participate, office staff must undertake a series of training (not everyone can take a sabbatical from their routine). Archaeological tourist activities are limited, whether held by history and culture enthusiasts or in regional tours.

6. Have you ever longed to observe a film being made or your favorite musician rehearsing? Such tours can motivate young people to pursue entertainment careers.

7. Pamper your pets to reduce stress. Many pet owners don't have time for walks or treats. These premium services target the wealthy.

8. A quirky idea to provide tours for imaginary couples or things. Some people marry inanimate objects or animals and seek to make their lover happy; others cherish their ashes after death.

#MISCideas

1. Fashion is a lifestyle, thus people often seek fresh materials. Chicken claws, geckos, snake skin casings, mice, bats, and fish skins are also used. Needs some improvement, definitely.

2. As fuel supplies become scarcer, people hunt for other energy sources. Sound is an underutilized renewable energy. The Batechsant technology converts environmental noise into electrical energy, according to study (Battery Technology Of Sound Power Plant). South Korean researchers use Sound-Driven Piezoelectric Nanowire based on Nanogenerators to recharge cell phone batteries. The Batechsant system uses existing noise levels to provide electricity for street lamp lights, aviation, and ships. Using waterfall sound can also energize hard-to-reach locations.

3. A New York Times reporter said IQ doesn't ensure success. Our school system prioritizes IQ above EQ (Emotional Quotient). EQ is a sort of human intelligence that allows a person to perceive and analyze the dynamics of his emotions when interacting with others (and with himself). EQ is suspected of being a bigger source of success than IQ. EQ training can gain greater attention to help people succeed. Prioritize role models from school stakeholders, teachers, and parents to improve children' EQ.

4. Teaching focuses more on theory than practice, so students are less eager to explore and easily forget if they don't pay attention. Has an engineer ever made bricks from arid red soil? Morocco's non-college-educated builders can create weatherproof bricks from red soil without equipment. Can mechanical engineering grads create a water pump to solve water shortages in remote areas? Art graduates can innovate beyond only painting. Artists may create kinetic sculpture by experimenting so much. Young people should understand these sciences so they can be more creative with their potential. These might be extracurricular activities in high school and university.

5. People have been trying to recycle agricultural waste for a long time. Mycelium helps replace light, easily crushed tiles and bricks (a collection of hyphae like in the manufacture of tempe). Waste must contain lignocellulose. In this vein, anti-mainstream painting canvases can be made. The goal is to create the canvas uneven like an amoeba outline, not square or spherical. The resulting canvas is lightweight and needs no frame. Then what? Open source your idea like Precious Plastic to establish a community. By propagating this notion, many knowledgeable people will help improve your product's quality and impact.

6. As technology and humans adapt, fraud increases. Making phony doctor's letters to fool superiors, fake credentials to get hired, fraudulent land certificates to make money, and fake news (hoax). The existence of a Wikimedia can aid the community by comparing bogus and original information.

7. Do you often hit a problem-solving impasse? Since the Doraemon bag hasn't been made, construct an Idea Bank. Everyone can contribute to solving problems here. How do you recruit volunteers? Obviously, a reward is needed. Contributors can become moderators or gain complimentary tickets to TIA (Tech in Asia) conferences. Idea Bank-related concepts: the rise of startups without a solid foundation generates an age as old as corn that does not continue. Those with startup ideas should describe them here so they can be validated by other users. Other users can contribute input if a comparable notion is produced to improve the product or integrate it. Similar-minded users can become Co-Founders.

8. Why not invest in fruit/vegetables, inspired by digital farming? The landowner obtains free fruit without spending much money on maintenance. Investors can get fruits/vegetables in larger quantities, fresher, and cheaper during harvest. Fruits and vegetables are often harmed if delivered too slowly. Rich investors with limited land can invest in teak, agarwood, and other trees. When harvesting, investors might choose raw results or direct wood sales earnings. Teak takes at least 7 years to harvest, therefore long-term wood investments carry the risk of crop failure.

9. Teenagers in distant locations can't count, read, or write. Many factors hinder locals' success. Life's demands force them to work instead of study. Creating a learning playground may attract young people to learning. Make a skatepark at school. Skateboarders must learn in school. Donations buy skateboards.

10. Globally, online taxi-bike is known. By hiring a motorcycle/car online, people no longer bother traveling without a vehicle. What if you wish to cross the island or visit remote areas? Is online boat or helicopter rental possible like online taxi-bike? Such a renting process has been done independently thus far and cannot be done quickly.

11. What do startups need now? A startup or investor consultant. How many startups fail to become Unicorns? Many founders don't know how to manage investor money, therefore they waste it on promotions and other things. Many investors only know how to invest and can't guide a struggling firm.

“In times of crisis, the wise build bridges, while the foolish build barriers.” — T’Challa [Black Panther]

Don't chase cash. Money is a byproduct. Profit-seeking is stressful. Market requirements are opportunities. If you have something to say, please comment.

This is only informational. Before implementing ideas, do further study.

How I monetized and sold an abandoned side project for $20,000

The Origin Story

I've always wanted to be an entrepreneur but never succeeded. I often had business ideas, made a landing page, and told my buddies. Never got customers.

In April 2021, I decided to try again with a new strategy. I noticed that I had trouble acquiring an initial set of customers, so I wanted to start by acquiring a product that had a small user base that I could grow.

I found a SaaS marketplace called MicroAcquire.com where you could buy and sell SaaS products. I liked Shareit.video, an online Loom-like screen recorder.

Shareit.video didn't generate revenue, but 50 people visited daily to record screencasts.

Purchasing a Failed Side Project

I eventually bought Shareit.video for $12,000 from its owner.

$12,000 was probably too much for a website without revenue or registered users.

I thought time was most important. I could have recreated the website, but it would take months. $12,000 would give me an organized code base and a working product with a few users to monetize.

I considered buying a screen recording website and trying to grow it versus buying a new car or investing in crypto with the $12K.

Buying the website would make me a real entrepreneur, which I wanted more than anything.

Putting down so much money would force me to commit to the project and prevent me from quitting too soon.

A Year of Development

I rebranded the website to be called RecordJoy and worked on it with my cousin for about a year. Within a year, we made $5000 and had 3000 users.

We spent $3500 on ads, hosting, and software to run the business.

AppSumo promoted our $120 Life Time Deal in exchange for 30% of the revenue.

We put RecordJoy on maintenance mode after 6 months because we couldn't find a scalable user acquisition channel.

We improved SEO and redesigned our landing page, but nothing worked.

Despite not being able to grow RecordJoy any further, I had already learned so much from working on the project so I was fine with putting it on maintenance mode. RecordJoy still made $500 a month, which was great lunch money.

Getting Taken Over

One of our customers emailed me asking for some feature requests and I replied that we weren’t going to add any more features in the near future. They asked if we'd sell.

We got on a call with the customer and I asked if he would be interested in buying RecordJoy for 15k. The customer wanted around $8k but would consider it.

Since we were negotiating with one buyer, we put RecordJoy on MicroAcquire to see if there were other offers.

We quickly received 10+ offers. We got 18.5k. There was also about $1000 in AppSumo that we could not withdraw, so we agreed to transfer that over for $600 since about 40% of our sales on AppSumo usually end up being refunded.

Lessons Learned

First, create an acquisition channel

We couldn't discover a scalable acquisition route for RecordJoy. If I had to start another project, I'd develop a robust acquisition channel first. It might be LinkedIn, Medium, or YouTube.

Purchase Power of the Buyer Affects Acquisition Price

Some of the buyers we spoke to were individuals looking to buy side projects, as well as companies looking to launch a new product category. Individual buyers had less budgets than organizations.

Customers of AppSumo vary.

AppSumo customers value lifetime deals and low prices, which may not be a good way to build a business with recurring revenue. Designed for AppSumo users, your product may not connect with other users.

Try to increase acquisition trust

Acquisition often fails. The buyer can go cold feet, cease communicating, or run away with your stuff. Trusting the buyer ensures a smooth asset exchange. First acquisition meeting was unpleasant and price negotiation was tight. In later meetings, we spent the first few minutes trying to get to know the buyer’s motivations and background before jumping into the negotiation, which helped build trust.

Operating expenses can reduce your earnings.

Monitor operating costs. We were really happy when we withdrew the $5000 we made from AppSumo and Stripe until we realized that we had spent $3500 in operating fees. Spend money on software and consultants to help you understand what to build.

Don't overspend on advertising

We invested $1500 on Google Ads but made little money. For a side project, it’s better to focus on organic traffic from SEO rather than paid ads unless you know your ads are going to have a positive ROI.

Who founded bitcoin is the biggest mystery in technology today, not how it works.

On October 31, 2008, Satoshi Nakamoto posted a whitepaper to a cryptography email list. Still confused by the mastermind who changed monetary history.

Journalists and bloggers have tried in vain to uncover bitcoin's creator. Some candidates self-nominated. We're still looking for the mystery's perpetrator because none of them have provided proof.

One person. I'm confident he invented bitcoin. Let's assess Satoshi Nakamoto before I reveal my pick. Or what he wants us to know.

Satoshi's P2P Foundation biography says he was born in 1975. He doesn't sound or look Japanese. First, he wrote the whitepaper and subsequent articles in flawless English. His sleeping habits are unusual for a Japanese person.

Stefan Thomas, a Bitcoin Forum member, displayed Satoshi's posting timestamps. Satoshi Nakamoto didn't publish between 2 and 8 p.m., Japanese time. Satoshi's identity may not be real.

Why would he disguise himself?

There is a legitimate explanation for this

Phil Zimmermann created PGP to give dissidents an open channel of communication, like Pretty Good Privacy. US government seized this technology after realizing its potential. Police investigate PGP and Zimmermann.

This technology let only two people speak privately. Bitcoin technology makes it possible to send money for free without a bank or other intermediary, removing it from government control.

How much do we know about the person who invented bitcoin?

Here's what we know about Satoshi Nakamoto now that I've covered my doubts about his personality.

Satoshi Nakamoto first appeared with a whitepaper on metzdowd.com. On Halloween 2008, he presented a nine-page paper on a new peer-to-peer electronic monetary system.

Using the nickname satoshi, he created the bitcointalk forum. He kept developing bitcoin and created bitcoin.org. Satoshi mined the genesis block on January 3, 2009.

Satoshi Nakamoto worked with programmers in 2010 to change bitcoin's protocol. He engaged with the bitcoin community. Then he gave Gavin Andresen the keys and codes and transferred community domains. By 2010, he'd abandoned the project.

The bitcoin creator posted his goodbye on April 23, 2011. Mike Hearn asked Satoshi if he planned to rejoin the group.

“I’ve moved on to other things. It’s in good hands with Gavin and everyone.”

Nakamoto Satoshi

The man who broke the banking system vanished. Why?

Satoshi's wallets held 1,000,000 BTC. In December 2017, when the price peaked, he had over US$19 billion. Nakamoto had the 44th-highest net worth then. He's never cashed a bitcoin.

This data suggests something happened to bitcoin's creator. I think Hal Finney is Satoshi Nakamoto .

Hal Finney had ALS and died in 2014. I suppose he created the future of money, then he died, leaving us with only rumors about his identity.

Hal Finney, who was he?

Hal Finney graduated from Caltech in 1979. Student peers voted him the smartest. He took a doctoral-level gravitational field theory course as a freshman. Finney's intelligence meets the first requirement for becoming Satoshi Nakamoto.

Students remember Finney holding an Ayn Rand book. If he'd read this, he may have developed libertarian views.

His beliefs led him to a small group of freethinking programmers. In the 1990s, he joined Cypherpunks. This action promoted the use of strong cryptography and privacy-enhancing technologies for social and political change. Finney helped them achieve a crypto-anarchist perspective as self-proclaimed privacy defenders.

Zimmermann knew Finney well.

Hal replied to a Cypherpunk message about Phil Zimmermann and PGP. He contacted Phil and became PGP Corporation's first member, retiring in 2011. Satoshi Nakamoto quit bitcoin in 2011.

Finney improved the new PGP protocol, but he had to do so secretly. He knew about Phil's PGP issues. I understand why he wanted to hide his identity while creating bitcoin.

Why did he pretend to be from Japan?

His envisioned persona was spot-on. He resided near scientist Dorian Prentice Satoshi Nakamoto. Finney could've assumed Nakamoto's identity to hide his. Temple City has 36,000 people, so what are the chances they both lived there? A cryptographic genius with the same name as Bitcoin's creator: coincidence?

Things went differently, I think.

I think Hal Finney sent himself Satoshis messages. I know it's odd. If you want to conceal your involvement, do as follows. He faked messages and transferred the first bitcoins to himself to test the transaction mechanism, so he never returned their money.

Hal Finney created the first reusable proof-of-work system. The bitcoin protocol. In the 1990s, Finney was intrigued by digital money. He invented CRypto cASH in 1993.

Legacy

Hal Finney's contributions should not be forgotten. Even if I'm wrong and he's not Satoshi Nakamoto, we shouldn't forget his bitcoin contribution. He helped us achieve a better future.

Using math to write efficient code in any language

Programmers design, build, test, and maintain software. Employ cases and personal preferences determine the programming languages we use throughout development. Mobile app developers use JavaScript or Dart. Some programmers design performance-first software in C/C++.

A generic source code includes language-specific grammar, pre-implemented function calls, mathematical operators, and control statements. Some mathematical principles assist us enhance our programming and problem-solving skills.

We all use basic mathematical concepts like formulas and relational operators (aka comparison operators) in programming in our daily lives. Beyond these mathematical syntaxes, we'll see discrete math topics. This narrative explains key math topics programmers must know. Master these ideas to produce clean and efficient software code.

Expressions in mathematics and built-in mathematical functions

A source code can only contain a mathematical algorithm or prebuilt API functions. We develop source code between these two ends. If you create code to fetch JSON data from a RESTful service, you'll invoke an HTTP client and won't conduct any math. If you write a function to compute the circle's area, you conduct the math there.

When your source code gets more mathematical, you'll need to use mathematical functions. Every programming language has a math module and syntactical operators. Good programmers always consider code readability, so we should learn to write readable mathematical expressions.

Linux utilizes clear math expressions.

Inbuilt max and min functions can minimize verbose if statements.

How can we compute the number of pages needed to display known data? In such instances, the ceil function is often utilized.

import math as m
results = 102
items_per_page = 10 
pages = m.ceil(results / items_per_page)
print(pages)

Learn to write clear, concise math expressions.

Combinatorics in Algorithm Design

Combinatorics theory counts, selects, and arranges numbers or objects. First, consider these programming-related questions. Four-digit PIN security? what options exist? What if the PIN has a prefix? How to locate all decimal number pairs?

Combinatorics questions. Software engineering jobs often require counting items. Combinatorics counts elements without counting them one by one or through other verbose approaches, therefore it enables us to offer minimum and efficient solutions to real-world situations. Combinatorics helps us make reliable decision tests without missing edge cases. Write a program to see if three inputs form a triangle. This is a question I commonly ask in software engineering interviews.

Graph theory is a subfield of combinatorics. Graph theory is used in computerized road maps and social media apps.

Logarithms and Geometry Understanding

Geometry studies shapes, angles, and sizes. Cartesian geometry involves representing geometric objects in multidimensional planes. Geometry is useful for programming. Cartesian geometry is useful for vector graphics, game development, and low-level computer graphics. We can simply work with 2D and 3D arrays as plane axes.

GetWindowRect is a Windows GUI SDK geometric object.

High-level GUI SDKs and libraries use geometric notions like coordinates, dimensions, and forms, therefore knowing geometry speeds up work with computer graphics APIs.

How does exponentiation's inverse function work? Logarithm is exponentiation's inverse function. Logarithm helps programmers find efficient algorithms and solve calculations. Writing efficient code involves finding algorithms with logarithmic temporal complexity. Programmers prefer binary search (O(log n)) over linear search (O(n)). Git source specifies O(log n):

Logarithms aid with programming math. Metas Watchman uses a logarithmic utility function to find the next power of two.

Employing Mathematical Data Structures

Programmers must know data structures to develop clean, efficient code. Stack, queue, and hashmap are computer science basics. Sets and graphs are discrete arithmetic data structures. Most computer languages include a set structure to hold distinct data entries. In most computer languages, graphs can be represented using neighboring lists or objects.

Using sets as deduped lists is powerful because set implementations allow iterators. Instead of a list (or array), store WebSocket connections in a set.

Most interviewers ask graph theory questions, yet current software engineers don't practice algorithms. Graph theory challenges become obligatory in IT firm interviews.

Recognizing Applications of Recursion

A function in programming isolates input(s) and output(s) (s). Programming functions may have originated from mathematical function theories. Programming and math functions are different but similar. Both function types accept input and return value.

Recursion involves calling the same function inside another function. In its implementation, you'll call the Fibonacci sequence. Recursion solves divide-and-conquer software engineering difficulties and avoids code repetition. I recently built the following recursive Dart code to render a Flutter multi-depth expanding list UI:

Recursion is not the natural linear way to solve problems, hence thinking recursively is difficult. Everything becomes clear when a mathematical function definition includes a base case and recursive call.

Conclusion

Every codebase uses arithmetic operators, relational operators, and expressions. To build mathematical expressions, we typically employ log, ceil, floor, min, max, etc. Combinatorics, geometry, data structures, and recursion help implement algorithms. Unless you operate in a pure mathematical domain, you may not use calculus, limits, and other complex math in daily programming (i.e., a game engine). These principles are fundamental for daily programming activities.

Master the above math fundamentals to build clean, efficient code.