I've been dreaming of writing this for so long.
About 2 years ago, Radewoosh posted a blog celebrating that he had solved all 865 problems on Project Euler.
As a (naively optimistic) high-schooler back then, I thought to myself: "Surely it can't be that hard, right?"
2 years later, there are now 965 problems, and I've solved all of them!!
I can’t even begin to describe how happy I am, and how wonderful the journey has been. Maybe I’ll write about it in another blog sometime. For now, I’ll answer some questions you might be thinking...
Literally, who asked?
No one, of course. But this achievement means a lot to me, and I hope that this post inspires someone out there.
How long did it take?
Kind of a difficult question to answer, actually!
Here's a general timeline:
- 2017 (11yo): Started solving Project Euler. Quickly gave up because it's too hard. Looked up solutions online (I swear I only looked at the first 100, sorry >.<). This is not the same account I currently have, FYI. (Challenge: can you find my old account?)
- 2020 (2021?) (14-15yo): Created a new account, SanguineChameleon. Started solving again. Got bored and deleted the account.
- Feb 2023 (16yo): Got reintroduced to Project Euler. Solved 4 problems or so on a new account, SanguineChameleon2. Didn't do much after that. I just left it there for a while.
- Sep 2023-Oct 2025 (16-18yo): Okay, for real this time. Let's try to solve all the problems!
Basically, it took 2 years. More or less.
What was the last problem you solved?
I'll be boring and say it was #965. But wait, isn't that problem super easy?
Yes. I pretty much solved all the problems sequentially. I never skipped any.
Why? Well, if I didn't do that, I probably would've ended up getting lazy and giving up. It was a way to force myself to be uncomfortable, to actually think about problems, instead of just solving those that were already at my level.
Okay, so what was your hardest/easiest/most favorite/least favorite...
All of those questions are ill-defined. If you asked me 10 times, I'd give 10 different answers.
Yes, I am human. I have opinions. But I don't want to influence people into thinking that some problems are harder/easier/better than others. You'll have to come up with those conclusions yourself, by actually solving the problems!
Though, if you really want to know, then feel free to poke me in the Project Euler Discord. We can have lengthy discussions about how problem ABC is the greatest problem ever proposed, or how problem XYZ should be removed from the site entirely :P
ZOMG! You must be some sort of math genius!
No. Not at all. In fact, I'm only taking my undergrad intro to calculus and linear algebra courses now, and they're quite "difficult".
Not "difficult" in the same way Project Euler is, though. I just find them incredibly dry.
I've never considered myself "good at math". The only things I'd say I'm good at are "Googling" and "wasting a whole afternoon trying to solve a problem".
Although, after talking to a few Discord members, I realize I haven't gotten my point across, so I'll try again.
Taking a look at the About section of PE...
The intended audience include students for whom the basic curriculum is not feeding their hunger to learn...
So yes, if there is one thing that I am good at, it's being willing to learn.
To be able to discover a mathematical truth, to make an incredible observation, or even just dip my toes into a new field of math. I think that's what makes Project Euler fantastic.
I'll leave the symbol-shuffling and fancy notation to the real mathematicians.
At the end of the day, I'm just a silly teenager with too much time on his hands.
So should I start solving Project Euler?
As with many things, my answer is simply "Maybe."
If you want to experience the joy of solving problems, then sure, of course!
But if you just want to solve PE to get better at competitive programming, then I'd suggest thinking carefully about it.
Yes, there's some correlation between being good at PE and being good at competitive programming. But they're still two very different things.
You don't have to be an LGM to be good at PE, and you don't have to be good at PE to be an LGM.
I think the biggest difference is that competitive programming is a lot more mechanical: you have to solve X number of tasks within Y hours. Also, some of the techniques are more standardized.
For PE, there is no time limit, and there are no standard problems. Each new problem is like a gift from the problem setter, and you are free to bang your head against the wall for however long you want.
There are many more differences, but this margin is too narrow, so I'll leave it at that.
Lastly, I'd like to thank the following people:
- Colin Hughes, for creating Project Euler. You've built something truly beautiful, and your site has changed my life.
- Radewoosh, for writing the initial blog. If I hadn't read it, maybe I wouldn't have done any of this.
- The Project Euler community, for setting brilliant problems and creating a wonderful environment to discuss problem-solving. I've only been in the Discord server for a few days, but I already know I'll enjoy my time here.
- My dad, for introducing me to Project Euler.
- My mom, for being incredibly supportive of her
insaneson. - You, for reading this blog!
Wait, ur dad is a cp'er too?
No, he just thought I'd be interested in PE :p
orz
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me: finally solved 4 Project Euler problems
SanguineChameleon: hold my 2 years
btw congrats
how do you even know what you are looking for when googling for math stuff, do you just open random things in hopes of getting inspired?
I know this won't be super helpful, but I'll just quote the website:
So yeah, just a combination of searching and getting lucky. But I don't think there are any problems that use too obscure knowledge, IMO.
Jesus christ. This comment made me feel intense physical pain.
Just curious, are you still continuing with Project Euler until you reach 1000 problems or more?
Reading this blog also makes me want to try Project Euler, but I’m not sure how to start. Do you think solving one problem per day is doable, or are there some problems that would take multiple days to think through?
I’ll probably keep going for the foreseeable future :)
The newer problems are definitely higher quality and harder overall. But that doesn't mean they're impossible. In fact, most of them are pretty approachable. I'd suggest starting with the latest 100-200 problems.
As for the solve time, it really depends on the problem. There have been days where I've solved 10 in a row, but there have also been times where I've struggled to solve something for nearly a week.
The difficulty ratings on PE are pretty accurate. I think anything < 40% should be solvable within a day.
congrats
I really wanna upvote this, but this number is too perfect for this post
Congratulations!
I am coming to this blog after solving 6 — 7 problems on PE as inspiration
Congratulations on completing Project Euler!
Bro beat the solo campaign GG
That's very impressive, congratulations!
Your story was really inspiring! I also want to try PE for improving my Math skill in CP, especially in combinatorics. So, can you please give me a short induction based on your experience? Thanks a lot.
Well, you asked for an "induction", so here's one:
To solve $$$X$$$ problems on PE, just solve $$$X - 1$$$ problems first, and then solve another one :P
No, but really though, just start solving! There's no need to learn any topics beforehand.
From the website:
I think that you are too modest and underselling the achievement ;) Currently only 9 different people in the world share with you this impressive feat! Not only that but if you check how many people have solved at least $$$90\%$$$ ($$$869$$$ problems) of the problemset, it's only 86 people in the world. At least $$$50\%$$$ ($$$483$$$ problems)? Only 488 people. Heck, even at least $$$25\%$$$ ($$$242$$$ problems) is only 2301 people. This shows that solving even the easiest quarter of them is already something rare.
So solving the entire PE takes some incredible consistenty, determination and skill. And even more, you did this in just 2 years, which is also a jaw droppingly short time! You really have something to be very proud of! Much congratulations!
It's about time you "dip your toes" in serious mathematics.
I don't like online CPers, effectively larping as mathematicians and the only math they ever did was vibe math. (PE's founder picking the 'euler' nickname is hilarious lmao).
Do pure mathematics. Get Gallian's and start doing group theory. Get to the big fields buddy because doing CP after some point is embarassing in my opinion.
Download Matlab and start doing theoretical physics and read Nature journal and copy their computations and tweak them for the shit's and giggle's and all that's. They'll tell you "muh computational models for engineers" but no it's just math, everything is math, you can't escape math. We live in Plato's wet dream and we will never wake up.
show your codeforces rating
xD. Lmao even.
My dude coping so hard rn
All these years spent to be mediocre solving already solved problems lol.
I could never get ragebaited to reach top 100 or top 10 to prove that it really is a pointless and stupid hobby for grown men. It's either an unserious learning activity for kids or for tech companies to exploit clueless human beings.
It's a performative manual labor for those who can't sit down and use pen and paper.
Pure Math rules.
Why don't you show me how to sit down to paper and pen your way into a living income?
Personally, I am a fan of theoretical mathematics but to be completely honest it's not for everyone and let's not kid ourselves pretending that everyone should be doing it... If you find it fun, good for you. But most people don't and that's okay, because, for example, they solve real problems instead of proving a theorem that has a 1% chance to get cited like three times in the next 25 years.
I never interacted with this website before and people here are saying "Theoretical mathematics" and are not reading my original message of running physics simulations and basically doing engineering stuff because that's infinitely a better career than whatever CS can bring. And btw, if you're passionate, you will get 100 citations in a few years. Citations in pure math is not what you people think it is.
Butthurt children feeling attacked and throwing a tantrum instead of listening is peak Reddit. I thought this website was a bit serious but turns out I'm literally talking to kids who have no clue what they're doing or what's going on out there.
Goodluck to you all.
I don't think it's about being serious, it's about the tone. "I don't like online CPers" feels like an attack on the whole community. If you want people to listen, you should treat both side as equal, rather than coming to the conclusion that the other is objectively better.
LOL.
I was referring to this: "Do pure mathematics. Get Gallian's and start doing group theory. Get to the big fields buddy because doing CP after some point is embarassing in my opinion."
I also find it ironic that you mention Reddit, considering your first message here. Look at this from the perspective of a random observer: the kid is 18 years old and makes a post about some sort of competitive programming achievement. Then some guy (you) on a burner account shows up and makes a Redditor-style gatekeeping rant tryinig to devalue the guy's achievements.
And about listening, you never really said anything of value. You just said that pure math is better and ended at it. You don't back your points up, you just say stuff like "infinitely a better career than whatever CS can bring".
Competitive programming is just a way to train your mind in problem solving and has quite a large overlap with the field of algorithmics which is quite useful. Nobody here is claiming that doing CF/PE makes you smarter than a mathematician or physicist, nor do those people title themselves mathematicians. This is a hobby website, what do you except if you come here and keep telling everyone that their hobby is stupid while your message reeks of bad faith?
And about the citations part, I am not devaluing writing articles but if you get deep into math, it's very likely that the stuff you write might wait a very long time before someone finds some use for it, no matter how good it is. But I do admit to having commited a hyperbole with the "3 citations after 25 years".
At first time reading this I felt an incredible physical pain. An incredibly hard read. I tried to give it some time to marinate and the emotions go so I can give a proper response.
What he did is an achievement but it's time to move on. This forum still worships this activity like there is nothing else to do and no other "step" afterwards. They all believe coding is all there is. They all pretend this isn't some game where you want number to go up by learning synthetic high-decay and low-complexity information that largely cripples you in real life. This is known in the chess community or Go community that competing past a point will not benefit your life in any way and it's a psychological disorder an obsession. This whole website, and "competitive programming" as an activity, a social game. Don't play social games.
If you're not curious enough about why doing pure math and computational physics the way to go then don't bother reading this or replying.
If you're curious then you must acknowledge that you have no idea what "competitive programming" is and how it overlaps with actual science or real world problems and applications. It's just a gimmick that served corporate interests and inflated egos. You're pretending math doesn't literally give you the same benefits you listed but at least infinities better. Even the problem solving process you're doing with every "puzzle" at leetcode or codeforces is an absolute tragedy to witness such a mindset being taught and practiced and encouraged. The people here handicap themselves and end up with no actual careers despite all the "hype" and struggle to find anything fulfilling.
Basically competitive programming is only for beginners and after that it becomes a classical case of useless specialization for the sake of "competing," where problems don't mean anything anymore and it's just connecting pieces to get points. If this is okay for you and not ringing any bells then proceed.
As for the "hyperbole" again you don't really know what you're talking about and what math or physics research actually is. Research and ask questions to know the answer as this is the limit of my patience.
Goodluck.
Ah yes lets just go to a website dedicated for competitive programming and tell anyone who does this is stupid, surely everyone will agree with me! Atp if you want to rant just go to reddit xD
Wow, this post actually motivated me to start too! I’ve solved 11 problems so far, and I’m really enjoying it. Didn’t expect Euler problems to be this addictive. Thanks for the post, and congratulations!
orz
Let's see if you can answer all the questions in the code forces or not? :-D
good job bro, orz
Nice, man.
I can't even register, tell me the answer of Problem Zero
I am solving 1 problem daily after reading this blog. Thank You for Motivating Me
I solved 70 Problems till Now. — Thank You So Much.
Most Of My Code runs under 1s in C++ with -02 Flag.
To know my current progress, you can visit the link. https://projecteuler.net/profile/the_commando_x.png
Today: Solved
76out of 972 problems (7.8%)Reached: Level 3 + Award 6
Profile: https://projecteuler.net/profile/the_commando_x.png
Yay!!! I got One Bonus Problem Today —
root13.Only 5 Bonus Problem exists — I got one.
It's been like 35 days since I started.
I am doing like 2 problem on average along with USACO consistently.
Yayyyyy!, solved
100 Problemsand reachedLevel 4TODAY. It took 6 week from29 Oct 2025— solving consistently each day.SanguineChameleon, Thank You So Much.
I am addicted to ProjectEuler.
https://projecteuler.net/profile/the_commando_x.png
Idk how I forgot to comment on this, but GJ M8!
Congrats on the achievement!
Earned One Percenter Award — Better than 99% — 109 Solved
Thank You SanguineChameleon
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