There still seems to be some inconsistency between my profile and the leaderboard. The former shows 51/200 solved tasks, while the leaderboard only shows 50/200. Can you please look into this?

Don't you hacking can be misused to make website judging too slow by adding lots of test data. I feel some limit like 500 or 1000 should be put on maxtests as per the capability of website.

Are you also planning to upgrade to the C++17 version? I feel it is a nice feature that is lacking currently.

While I appreciate the effort, I don't like the fact that there are so many platforms and a lot of problems are repeated. It means a lot of time was wasted.

But is it rated? Don't downvote please, it's my birthday tomorrow

Would it be possible to add support for PyPy? I generally enjoy solving tasks in python, especially codegolfing with it, but with the 1 s TL it is many times really hard / impossible to get cpython to pass.

On the task Sum of Four Values, I think the judge may be wrong... specifically, the output section asks for any solution, but I think the judge checks whether the provided answer is identical to its own.

The statement for Grid Paths says "from the upper-left square to the lower-right square," but the diagram and test data match "from the upper-left square to the lower-left square."

Its really helpful now to filter the problems based on tags. Maybe you can add some more problems on DP :)

you can now hack submissions and improve the quality of tests

when you're lazy to make strong tests

There seems to be an issue with Palindrome Reorder. I can see an AC submission which just prints the input back without forming a palindrome.

Can't something be done for the multiplier of some slower languages? 50% of my Java Solutions get TLE.

it's tough for learners like us. how do we know the solution if we cant solve it. there's no point not knowing the solution.

Is there a way to reset password? I'm pretty sure I have an account, but can't recall the password.

Is there any way to hide the tags shown on the website? I want to try the problems on my own first without any hints.

Can you please have code of others viewable ?

In the problem Nearest Smaller Values, according to the constraints $$$1 \leq x_i \leq 10^9$$$ but in test cases 4, 5, 9 and 10 some $$$x_i$$$ are negative.

I'm pretty sure the checker for Labyrinth is wrong. Currently the solve count is 0/109.

The statement for Monsters says $$$1 \leq n,m \leq 2500$$$, but when i try making n=1001 i get invalid input(the same test with n=1000 and the last line removed doesn't get invalid input)...

The model solution for High Score seems to be wrong; everyone has WA now.

Hey, the latex for these are not properly formatted (e.g. this one)

There was rejudging of the problem String Transform recently, added new test case bb#aaa. Alas, correct output is expected as ab#ab, can you fix it, please?

UPD: Seems no original string exists corresponding to the input case bb#aaa.

I'm trying to do this dp problem (coins combinations II): https://cses.fi/problemset/result/244945/ . However, when I submit the code I get runtime error on some of the test cases. I tried some of the test cases that gave me runtime error locally, and everything went fine.

Here is my submission: https://cses.fi/problemset/result/244945/

PS: I used exactly the same compilation command specified here: https://cses.fi/howto/ and I have the same version of g++ (7.4.0)

Thanks for your great work !

Hello pllk. Would it be possible to have pdf versions of the problems? Or even just a single pdf containing all problems or maybe one pdf for each part of the problem set?

I really like both the competitive programmer's handbook and the cses.fi problemset.

However, I noticed that some problems can't be solved "normally" using python3 because the constraints are too large. For instance my python3 implementation of https://cses.fi/problemset/task/1192 takes 1.5s on some inputs.

I know the emphasis is on C++, but it wouldn't hurt to reduce the constraints a bit to make the problems solveable in all languages.

If you add editorials for the problems, this platform will be the best place to practice cp.

I have developed a command line program just like "leetcode-cli" for CSES.

Github Repository

It supports

• login
• list problemset
• view problem statement
• submit problem

On Cyclic Array:

9 35 2 17 30 35 14 21 22 6 12

It says that the correct output is 6, but [30],[35],[14,21],[22,6],[12,2,17] is a division into 5 subarrays...

In the task Food Division, the sample explanation says

Explanation: Child 1 gives one unit of food to child 3, and child 2 gives one unit of food to child 3.

In fact, child 3 gives one unit of food to child 1 and one unit of food to child 2. I think the explanation confuses the arrays a and b.

Great site, great problems, great book. Thanks pllk.

Is there something special about Playlist's Test Case #12?

My std::map solution passes but unordered_map, gp_hash_table, cc_hash_table fails miserably on that test case.

I even used custom hasher, as described in Chilli's blog:

const int RANDOM = chrono::high_resolution_clock::now().time_since_epoch().count();
struct chash {
    int operator()(int x) const { return x ^ RANDOM; }
};
gp_hash_table<key, int, chash> table;

    unordered_map<int,int> mp; // change this to any hash table
    int n = read(); // read() returns an integer from input
    vector<int> v(n);
    generate(all(v), read<>);
    int ans = 0;
    for (int l = 0, r = 0; l < n; ++l) {
        for (; r < n && mp[v[r]] == 0; mp[v[r++]]++) ;
        mp[v[l]]--;
        ans = max(ans, r - l);
    }
    cout << ans << el;

EDIT: Niel's custom hash worked!

How does CSES problem set compare to cf problem ratings?pllk

I successfully hacked a solution 4 days ago, but the page of the hack says "Test update status: Waiting confirmation from admin" and I can still see that solution on the hacking tab. What's going on?

In Static Range Minimum Query I tried to hack my own solution with a sorted array test case. But it gives Invalid Input. Even the Example Test given gives Invalid Input when submitted as a txt file. Am I doing something wrong?

You can refer to my repository on github, where i have solved many of the CSES problems & am still updating those solutions. I would also be giving a small editorial of the general idea about the solution approach: Link : https://github.com/MojoAlpha/CSES-Problemset

In Inversion Probability, it's possible to make test cases such that the answer is very close to $$$\frac{n+0.5}{10^6}$$$ for some integer $$$n$$$, meaning that solutions using floating-point numbers can end up being incorrect(for example, one of my recent hacks has the answer of about 53.4183365000000000000943). I don't think forcing people to calculate the exact answer is a good idea; it would be better to change the problem to something like allowing a relative or absolute error of $$$10^{-6}$$$.

Another thing to add to this: on the test case

the judge's solution is 90.384581, even though the exact answer is about 90.3845815000000000006058757, so the solution should be 90.384582.