Data Structures and Algorithms

Just wanna give a huge thank you to this sub for helping me find my dream job and hopefully pass on some stuff from my experience that may help any other aspiring devs.

Let me start this post off by saying

THANK YOU, THANK YOU, THANK YOU!!!

And that goes to all of the people here that have helped me over the last few months. Somehow, someway I finally got my dream job working as a Software Engineer at a startup in Chicago. Just got off the phone with HR and my heart skipped a beat, and my salary has more than doubled(!) going from a database dev to SE.

I've made a lot of posts here asking for help, advice, and recommendations and the community here is always extremely helpful and patient. I was going through a serious rough path of depression thinking maybe I made the wrong career choice or that I wasn't smart enough, but this sub truly helped me get out of my funk and essentially changed my life forever. Unlike most other programming forums where egos, condescending attitudes, and a general lack of empathy to a novice coder can run rampant, here I've run into almost all positive and helpful people, so I just wanted to again say thank you. I wanna give a personal thank you to:

u/swissgoat, u/schwede, u/veeberz, u/throwies11, u/Roxxo9001

and a super special thank you to u/ibsulon and u/mansfall (I owe you reddit gold!)

I wanted to give a rough summary of what my interview process was like and how I prepared just in case someone else out there learning programming knows it's absolutely possible if you put the effort in.

A couple months ago I decided I wanted to make the switch to SE after realizing that dealing exclusively with SQL all day every day wasn't exactly the most fun thing in the world. I started off by settling on C# and doing some small projects in Unity with a few online tutorials to get my feet wet. I had already started putting in applications but never did I imagine I'd get a call within the first week, but I went in anyway and got absolutely grilled. I couldn't answer any of the questions and felt like an absolute idiot. Afterward I decided I needed to get my fundamentals up to par and watched the Bob Tabor Beginner C# course on Microsoft Virtual Academy after having it recommended to me here. The course was way better at explaining the basics than any of the resources I'd found on my own and even the stuff I checked out from the sidebar. I kept coming back and getting advice and recommendations from the people here and could feel myself improving. Eventually I get recommended this course by u/ibsulon in order to strengthen my computer science fundamentals, which was incredibly helpful. Fast forward a few months and I start to apply for jobs. Not even 24 hours later I have an interview scheduled for the end of the week. While I was in the midst of freaking out due to the PTSD from my last interview, I made a post asking for any advice for interviews and got a bunch of great feedback! Specifically, u/mansfall and his comment really helped me prepare for the interview as almost everything he posted was a part of the assessment they gave. Earlier today I finally got a call back from the company with the good news! I just want everyone to know i'm extremely grateful, and to those out there still trying to find work or are learning with a career in mind, you can do it!

How do I spend summer productively so that I'll be ready for interviews / become a better programmer?

Hi guys, I'm planning to learn full stack web developing during the summer. (just to touch on it, not going to go crazy on it. Just a little side project on the side, get exposed to javascript, etc.)

Aside from that, what can I do to spend the summer productively? My goal is to eventually get into a BIG4 company, but ultimately be knowledgeable enough to differentiate between an inefficient code and an efficient code, be confident in whiteboard coding.

I have some candidates to show you guys:

Competitive Programmer's Handbook

Algorithms I from Coursera

Master Algorithmic Programming Techniques

Other books I've considered are Clean Code and CTCI - but those I will be doing over slowly for the next year or year and a half.

There was a data structures / algorithm course that used C++ in coursera but that seems to be gone =(

I'm mainly going to concentrate on C++ and Java because these are languages that I'm most exposed to and I will be using it for the courses in upcoming Fall semester.

My level of programming is in between beginner and an intermediate.

tl;dr: level of programming = between beginner and intermediate, trying to get into BIG4, perform well in interviews and become a better programmer. What do you recommend I do?

I know it is a lot to ask only within 2 months and a half (about), I'm just trying to get to the intermediate level with decent knowledge of data structures and algorithms.

Recommendations welcome, thanks in advance!

[Request] Coursera Data Structures and Algorithms Specialisation course

there are 6 courses in this specalisation..only the first is available in 1337x and snahp.it ..can anyone upload the remaining 5 courses..

coursera link https://www.coursera.org/specializations/data-structures-algorithms

Course 1 Algorithmic Toolbox Course 2 Data Structures(already uploaded , this post) Course 3 Algorithms on Graphs Course 4 Algorithms on Strings Course 5 Advanced Algorithms and Complexity Course 6 Genome Assembly Programming Challenge..

Need Help With Algorithms And Data Structure

I started solving problems in April. I have solved 70 problems on LeetCode, easy-63, medium-6, and hard-1. On HackerRank I have solved around 78 problems(95% easy). I am participating in every LeetCode contest as well. I am taking Algorithms and Data Structure course (link), currently I am on the 3rd week section of Data Structure course.

The problem is that even after I am done with so many problems I am still unable to solve many easy questions, solving medium level questions is a distant dream. Today's LeetCode contest broke me hard, I wasn't able to solve even one question.

I am completely lost at the moment, confidence is down, I can't just suck at Algorithms and Data Structure.

Any help will be appreciated, thank you!

Is it reasonable to expect that writing idiomatic Haskell comes with a performance penalty?

Hi /r/haskellquestions, just to give some background on this question, I've been following the Data Structures and Algorithms specialisation on Coursera I've been having a lot of trouble implementing a lot of the programming assignments with the required complexity. Most of the time it's because !! and ++ are slow or that the algorithms given in the lectures rely on a mutable data structure.

Most of the time I can get around these by using arrays, sequences and mutability. However, whenever I do that, my code looks like crap. It doesn't feel like I'm writing 'idiomatic' Haskell. What I'm wondering is that, do you find that your Haskell code can be just as pleasing/beautiful/idiomatic whenever you have to use mutable arrays instead of lists?

UC San Diego's Data structures and Algorithms course is great.

https://www.coursera.org/specializations/data-structures-algorithms

Which Specialization is more suitable?

TLDR;

Which coursera specialization is better for algorithms and data structures (Standford's or UCSD's)

Hello there,

I'm currently a first year computer engineering student, almost finished my first year though, I took two programming languages courses this year (I had no prior knowledge), I took both MATLAB and C++ both courses that had some advanced concepts like OOP,Polymorphism ,I didn't take separate algorithms or data structures courses,they aren't taught in my college as separate courses -I guess- I might be unaware of the syllabi though, I prefer self learning anyways, however I'm planning to study them this summer, so I found two coursera specializations and I'm hesitated which one would be more suitable.

However those are the links for reference, and advice is always appreciated! , And thanks in advance! :)

1_Data Structures and Algorithms Specialization - UNIVERSITY OF CALIFORNIA SAN DIEGO

2) Algorithms Specialization - Stanford

I have no comp sci or discrete mathematics education , but I wanted to take the following course (https://www.coursera.org/specializations/data-structures-algorithms), which stipulates the following prerequisites:

"Basic knowledge of discrete mathematics: proof by induction, proof by contradiction."

Would it be possible to learn proof of induction and contradiction via a crash course with high school math? Or is there too much prerequisite knowledge?

Im asking because I dont have the time to go back to school at this point, but i do want to learn how to develop clean and efficient code.

buddy to work through Algorithms and DS specialization on Coursera

Hello everyone, Just learned about this sub through r/LearnProgramming today. I'm working through the Algorithms and Data Structures specialization on Coursera. I almost finished the second course, Data structures. Wondering if anyone is working on this course or interested in working on it.

I'll be honest, I've gotten a bit lazy after receiving a full-time offer from a Big 4, but would love a programming buddy to work through the whole course with!

https://www.coursera.org/specializations/data-structures-algorithms

That’s the DSA series I’m working through on Coursera. I don’t have much to review yet. Only started it last week. You can audit for free, it just doesn’t allow you to do the assignments. If you find a textbook, I’m sure there will be exercises to practice. Then just pay the fee at the end if you really want the assignments and shareable cert.

This is pretty popular on EDX and Coursera:

• Data Structures and Algorithms Specialization

This is what interested me to start this course:

>No other online course in Algorithms even comes close to offering you a wealth of programming challenges that you may face at your next job interview.

After completing CS50, followed by a few courses, I want to jump into Data Structures and Algorithms. Any recommendations on where to proceed?

Finished CS50, loved it. Finished Automate the Boring stuff, loved it. Took a Tableau and an advanced excel class for work, but now want to get back on the programming side. I found a coursera specialization in Data Structures and Algorithms, but wasn't sure if it would be the next right move (https://www.coursera.org/specializations/data-structures-algorithms?action=enroll#faq-list). Any and all advice appreciated.

It's just not just a vital skill, it's the only thing that matters in placements too. Especially for good companies, as they only care about your problem solving skills in DS + A. So it will def help you tons in 4th year.

The best and most comprehensive resource I could find when I wanted to learn DSA was this course on Coursera: https://www.coursera.org/specializations/data-structures-algorithms

They start from very basics of DSA and assume you know atleast one programming language. They also help you actually solve the problem rather than just throw the solution at you. Now the course isn't free, and I was able to access it cuz my college, Manipal, has partnership with Coursera so I get these courses for free.

But you can still access the main content of the course, you just won't get the certificate. I think you won't be able to submit answers either, but you can see the questions and solutions.

Best thing about this course is for every problem they provide the solution in 3 languages (c++, java, python). Since you already know C, i would suggest getting familiar with c++ as it's not too different from C and is the best language for DSA.

There's also a course by Stanford on Coursera, but it's more in-depth towards theoretical part, rather than problem solving like this course.

That's awesome! It's essentially a CS1 course (intro programming), so definitely nothing as advanced as DP, greedy algorithms, etc. :-)

If you want to refresh your memory about those topics, I highly recommend the following Coursera specialization, developed by some of my colleagues:

https://www.coursera.org/specializations/data-structures-algorithms

While i dont know of a website similar to the Odin project.
You can enroll in this coursera specialization

https://www.coursera.org/specializations/data-structures-algorithms

Coursera specialization

Just do 1st, 2nd and 1-2 weeks of 3rd course. Skip all the proofs and naive implementations. If you have basic idea of what greedy, dp etc is leave course 1 for last.

HTML. Why? Because you straight away see your code doing something. This is the hardest part of this industry - staying motivated or enjoying it enough to keep learning. Learning backend languages such as Python or Java is basically just outputting stuff to the console initially.

So I would recommend - 1. HTML - Not a programming language but very easy to learn and your effort is visualized straight away. 2. CSS - Add styling to your HTML. Change fonts, color, etc. 3. JavaScript - This is an actual programming language. Once you get the hang of it, you can fiddle with your browser's DOM to make your pages more user friendly.

At this point, you're a frontend developer. Not maybe professional grade but definitely competent.

1. NodeJS - This is JavaScript on the server. Since you already know JavaScript at this point, you can easily understand backend programming with NodeJS.
2. MongoDB - This is a really popular database used with NodeJS, and other languages too.

At this point, you can perform CRUD (create, read, update, delete) operations and can call yourself a fullstack web developer. Again, not a professional one.

How do you become a professional one? Start building projects. Anything. Tons of examples online for inspiration.

As you build them, you'll find that you're repeating a lot of stuff. This is where frameworks come in. They make it easier for you to reduce repeating common tasks. AngularJS is popular on the frontend and ExpressJS on the backend. Once you've learnt these, you know MEAN stack (MongoDB, ExpressJS, AngularJS, NodeJS). You can basically build any application with this.

You can develop stuff on your computer but how do you get others to use it? You deploy your application to a server. Cloud is pretty popular for this. Amazon Web Services, Heroku, Azure, etc.

Congratulations! You're now at a point where you can pretty much pickup any language or technology and build shit.

Recommended courses - * All of the stuff I mentioned above can be learnt at FreeCodeCamp. It's free and you can learn on your own time. * I don't know if you have a computer science background but it's good to know some algorithms and data structures. UCSD's professors teach Data Structures and Algorithms Specialization on Coursera. While there's a fee advertised, you can audit the courses for free.

FYI - This was my path to a software job.

No problem, might be worth checking out this course which has just started. I can't vouch for it, but could be interesting.

Coursera's data structure and algorithm course free alternative?

Is there any free alternative to this course? https://www.coursera.org/specializations/data-structures-algorithms

No, I really struggled to find good courses online. Like I said, I took Grantham's online DSA course, but it was abysmal. They gave me an A on all assignments (even when I was too busy to finish one all the way). I retook a in person DSA course at the University of Wisconsin–Madison. Cost me a pretty penny ($1,400) but I didn't want to apply to grad school without an official DSA under my belt. Ended up with an 89.8%, but considering I was working full-time, I am pretty proud of that score.

I also took the Coursera courses on DS&A in order to fill in gaps in my knowledge. I didn't mention Coursera because they are not accredited. But their online platform is actually a great tool in terms of offering that "in-class" feel. They quiz you in the middle of lecture videos, provide quizzes, and tests. They can't really solve the Google-fu portion of quizzes and tests, but the questions are still challenging. The coding assignments are also decently structured, but you need to push yourself most of the time without cheating. Online answers always exists – especially for the well known courses.

That being said, I did take an online course with FootHill Community College when I lived in CA. It was intermediate C++ (everything OOP + Linked Lists + basic sorting algos). That was a great course. I would have taken their advanced C++ (trees, graphs, more advanced sorting / searching), but they kept filling up on me.

Good courses do exist, but they require some digging around. In my experience, if you can find a local, accredited, public community colleges, then you're going to get a decent experience. If they are local, you can drive down and speak with the professor. You can feel assured of their accreditation. You can also more easily "hide" the online portion by just making your resume/transcript look like:

>MyCity Community College
>
>4 credits Introductory C++

It often looks better than:

>Online College
>
>4 credits Introductory C++

It really depends on your goals:

1. Going to college? You need an accredited course with some decent instructors. You'll probably want a public college so when you apply, other institutions "trust" your background
2. Getting a job? You might be better off with Coursera as they are more affordable and honestly do a decent job of presenting the information. Jobs don't really care about transcripts. They just want you to be able to do the job.
3. Just interested? Do whatever you feel!

But I highly recommend trying to stay local if you're looking to transfer to a college and get a good education in the meantime. I can't really justify why I feel this way... I guess it's because I had the best experience when I wasn't attending 3 different online colleges simultaneously. Staying local allowed me to stick within the same system for as long as possible. Once I got into those more advanced courses though... it became almost impossible to stay local and in a community college. I found some courses at SDSU but they are much more expensive. So, it's a tough call.

Honestly, part of my strategy was "take courses anywhere for credits learn on my own along the way". I can't really recommend that because it's a waste of money and time. But I have to admit, that was how I handled it in my own, desperate, way.

This one?

https://www.coursera.org/specializations/data-structures-algorithms#howItWorks

The course you listed is really in depth, you may never need to go that far in unless you are building a framework of sorts.

The one below more relevant if you are looking at CS.

https://www.coursera.org/specializations/data-structures-algorithms

The thing is that in my opinion, you can take the entire "specialization" but the chances of you using it all is probably very slim and after a few years you will probably not even remember much. I think a good understanding of the basics is all you need.

Coursera has a track done by University of San Diego. You can take the individual courses for free if you don't care about the cert. If you're broke, you can also apply for financial aid and get the cert for free. https://www.coursera.org/specializations/data-structures-algorithms

Hey are you planning to create a discord server or anything? Will be much easier to communicate and motivate each other. I just started this course: https://www.coursera.org/specializations/data-structures-algorithms? Doing the free version and on the first course 'Algorithmic toolbox'. I don't know how closely will I follow it. But will use it as a guide. Let me know if you create a server.

Yep. Grind away. I would say take an undergrad algos course like this one beforehand if you are worried about grasping the material: https://www.coursera.org/specializations/data-structures-algorithms. Since it's a coursera course, you can take it easy and not necessarily do everything. That should get you settled.

I recently started preparing for interviews and I tried all of the courses available in coursera, at the end this was by far the most complete and comprehensive https://www.coursera.org/specializations/data-structures-algorithms

UCSD - Data structures and algos

I just recently got a new job I'm pretty happy with, but along the way I bombed some leetcode and DS&A questions in other companies.

Looking for a course that I can use to brush up on DS&A before I grind leetcode for the next job. Anyone use the UCSD Coursera course? Worth it?

https://www.coursera.org/specializations/data-structures-algorithms

Is it this one? https://www.coursera.org/specializations/data-structures-algorithms

I'll check it out, thank you for your help.

As of now, I am familiar with the basics of programming (loops, arrays, functions, file I/O, 2D arrays, and recursion). I am interested in taking this specialization on Coursera, https://www.coursera.org/specializations/data-structures-algorithms. I was wondering if you guys could please tell me what other concepts I should learn first before taking this specialization. I don't want to move too far ahead and skip fundamentals.

I too am in the same position, I have decided to do the UCSD course on coursera and simultaneously practise on leetcode/hackerrank.

For python, see my reply for u/vishkv I've given him some resources about python. You can study this on coursera.

My progress has been excruciatingly slow. I started learning python in January, then did some data science specialization and learned pandas and it's ML libraries. Then did a little bit of backend in django. After that, I did a project on ML which really boosted my coding skills. Then I learned about databases for maybe a week. Finally I completed the Andrew NG machine learning course which gave a really good foundation of what to expect in machine learning. It was a heavy course(at least for me). Now, I'm again learning backend in django. I'll learn excel afterwards(I know that's kinda going backwards but excel is super easy and useful and won't take much time to learn). I'm also planning to do some good projects in Machine Learning and start from kaggle.

​

If I can give you one advice, it'd be start preparing from Data Structures from right now. They're really heavy stuff, so it's much better to devote 30 minute to an hour daily instead of cramming them up because you can't cram them. They're like math, you can't just do it in less time, you gotta practice. So start slow, but give them some time don't save it for the end trust me.

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I'm sorry if so much info looks overwhelming but some of these things didn't took me more than a week to complete so they're not that hard

I’m currently learning data structures and algorithms as a computer science student, so my advice might be biased to my time as a student, but here goes nothing:

1. If you’re a student, focus on your Fundamentals of Algorithms class (idk what it is at other schools) and your CS2, CS3 classes (Or your Data Structures class). They are designed for this very purpose.

2. If you want to go past school curriculum or are learning on your own: audit this course it helped me a ton with my own classes and if you audit it, you get it for free and you can work at your own pace.

3. Lastly, read medium articles, word for word, on the subject. People (as far as I’ve seen) who write these articles try their best to explain complicated or esoteric concepts as simple as possible and when a concept is condensed to its most essential bits, every word is important.

Hopefully this helps! Good luck!

I don's have a specific resource in mind, but checkout this coursera page (I googled it, haven't taken this course myself but UCSD is a good school)

https://www.coursera.org/specializations/data-structures-algorithms

As you can see, they have 5 courses.

I would personally start with course 2 (data structures) before course 1. I would say course 1 and course 2 are the basics. if you like the first two courses and want more advanced things, course 3, 4, and 5 look good.

For your second question, the general answer is no. A machine is a machine, just a collection of compute, memory, storage, and networking resources. Of course you have more control and visibility on your local machine (or machines), you can see and modify how things are connected, etc... But unless you are programming a High-frequency trading algorithm (or any thing that really requires extreme optimization at the hardware level), then I would say the infrastructure will not have a significant impact on the way you design and structure your code.

I'm sorry to tell you this, but there are no shortcuts in programming. The only way you are going to place out of 131 is by having a very good understanding of programming fundamentals. With that being said, I will give you the resources that I used to teach myself 120 and 121 when I was in high school.

First and foremost, I recommend the C++ tutorial on https://www.cprogramming.com/

It is very condensed unlike a C++ textbook and has a few practice problems that you can do. If you get up to polymorphism and inheritance, you will already have an equivalent knowledge to 120 and 121. After this, it would help to see the tutorial on www.cplusplus.com which is a bit more advanced (and provides better tutorials on pointers).

CPSC 131 is data structures. This is your first real Computer Science course. In 120 and 121 you have learned the basics of C++, but 131 is rooted in theory. My main advice for you is to think modularly when attempting to solve a problem. First think about the task you want to complete, then break it down into the classes, objects, and methods you will need to complete this task. Only then should you start writing code.

Most students fail Data Structures because they try to approach the problem line by line. The first four courses in this online specialization are equivalent to a full course on data structures: https://www.coursera.org/specializations/data-structures-algorithms

I wish you luck.

EDIT: I also feel the need to mention that generally, Udemy courses are not rigorous enough to provide an equivalent experience to a class. Coursera can be good. I have not tried Udacity, but they have some courses that are equivalent to a college level class.

One of the Data Structures & Algorithms tracks on Coursera is a bit similar. You submit your sourcecode, and the Coursera robots compile & run it on input they don't share with you. Your solutions need to be efficient, so a brute force approach with a naive algorithm will fail. It's fun.

Take a free Coursera course on Data Structures and Algorithms.

Hm, yeah... in the meantime I'm studying the same on Coursera. Awesome material, but it's paid only though if you actually want to upload homework.

https://www.coursera.org/specializations/data-structures-algorithms

you can do the exercises in c#

totally recommended

You can check these out :

Coursera - Data Structures and Algorithms Specialization

Runestone - Problem Solving with Algorithms and Data Structures using Python

UCSD Extension is a joke. I've written plenty of times about it already. The DS&A course can be finished in one/two days. 7 or 8 front-loaded homeworks that don't require depth in DS&A to complete, no exams, drop the weakest HW grade. Everyone in the class gets easy As.

This Coursera specialization from UCSD plus some folks of HES, however, is no joke: https://www.coursera.org/specializations/data-structures-algorithms . Lectures are average/bad and instructors not very skilled at teaching (except for one), but covers the entire DPV book and provides mathematical proofs in the lectures.

Have any of you tried to find material to preface for tough CS courses?

(Before I get downvoted to Hell), It's safe to say that CS 374 has gained quite a bit of notoriety for being one of the toughest and most time-consuming classes a CS major would have to take.

I am currently working on the Data Structures and Algorithms Course by Coursera (it's by San Diego), and here's a link:

https://www.coursera.org/specializations/data-structures-algorithms

I know this is probably going to be way, way insufficient for the rigor of the CS 225 and CS 374 classes, because Coursera is NOT the university experience, as great as its resources are.

What are you guys's methods for making your life in tough CS classes like 225 and 374 just a little bit easier?

Status: Accepted (by Dept)

Application Date: 02/08/2019

Decision Date: 03/28/2019

Education: George Mason University, BS, Mathematics, 3.4

Experience:

<1 yr Data Scientist, government consulting, Python/PostgreSQL

1 yr Data Analyst, government consulting, Excel/Tableau/Python

5 yrs U.S. Navy submarine force, no CS experience

Recommendations: 3 (all submitted by 02/15/2019): supervisor from the Navy, professor who was my undergraduate research advisor, and latest employer.

Comments: My CS experience was limited to some undergraduate computational mathematics research (Matlab), one undergraduate Python course, currently ongoing Coursera Data Science specialization, and the last 1.5 yrs of my work experience. Given my minimal CS background, was planning on doing a Data Structures and Algorithms course this summer; https://www.coursera.org/specializations/data-structures-algorithms.

Looking back on the many hours I've spent anxiously refreshing this thread, I can't say whether it was helpful or harmful to my psyche but it was certainly informative haha.

Thanks to those who shared on this thread and if anyone is interested in setting up a regular meet-up in the DC area this fall or has any info on UCSD's data structures course, feel free to PM me!

I'd say it's more difficult than CS 330 and the workload is significantly higher. CS 330, however, had less online resources to refer to. For CS 483, there are tons of YouTube videos that can help you understand a specific concept or algorithm. Additionally, CS 330 had a couple projects but CS 483 is more homework focused (at least when I took it with Nordstrom and with Kosecka).

I'd suggest studying a bit during the summer. Princeton has some good courses on Algorithms (Part I , Part II) and Analysis of Algorithms. If you study a bit over the summer, you can hit the ground running and have one less thing to worry about come Fall.

I don't think you can get university credit, but there's some courses which offer a certificate to show you completed the course

https://www.coursera.org/specializations/data-structures-algorithms?

https://www.coursera.org/specializations/data-structures-algorithms

As far as I know, those two are considered the reference algorithm courses. But if you want something that is less theory-oriented, more practical, I've heard good things about UC San Diego's algorithms course:

Data Structures and Algorithms Specialization

In this one, you get to implement a ton of algorithms.

If you do take this one, let me know how you liked it. I'm considering taking it myself.

Have you taken this specialization and can vouch for its excellence?

Curious how it might compare to this other one which I have been thinking about and was highly recommended by colleagues.

I did Coursera's Algorithms and Data Structures a while back and remember them having good exercises (good course too).
Not sure how accessible the exercises or materials are if you're not looking to follow the course schedule but I'd still suggest it's a worthwhile undertaking for anyone looking to go from beginner to intermediate Java developer.

https://www.coursera.org/specializations/data-structures-algorithms

If you're open to paying for one, a big deal when it comes to getting jobs in the CS space is around being able to pass programming interviews, which like to test your ability to navigate different data structures and write algorithms that'll be reasonably efficient.

If you're looking for a paid certificate course, one I recommend is this Coursera Data Structures & Algorithms course series by UC San Diego, which covers a lot of concepts in DS&Algos and includes an autograder that'll test/benchmark your code for you. I forget what the monthly cost is, but it gets you access to all 6 courses in the series, so if you blaze through them quickly it'll be more cost-effective. If you haven't taken any kind of a DS&Algo course, you'd seriously benefit from this, 'cus at least where I'm from (USA), employers have a big kink for testing you on that content in interviews.

If you need to, you could also probably work the shit job and continue learning to code on the side as much as possible while you apply for better positions. When I started school I worked minimum-wage jobs for my first years until I had the skills to move up to cooler and better-paying positions, it just took a lot of trying. If you really enjoy tech stuff, don't give up hope :)