MikeMirzayanov's blog

Welcome GNU G++23 14.2 (64 bit, winlibs)
By MikeMirzayanov, history, 25 hours ago, In English

Hello, Codeforces!

Together with Vladosiya, we've added support for the 64-bit g++14 C++23. You can find it under the name GNU G++23 14.2 (64 bit, winlibs).

If you're using Windows, you can easily install it via our minimalistic package manager, PBOX, by running the command pbox install gcc14-64-winlibs.

Thanks to the WinLibs project! We used the distribution from this page: https://winlibs.com/ GCC 14.2.0 (with POSIX threads) + LLVM/Clang/LLD/LLDB 18.1.8 + MinGW-w64 12.0.0 UCRT - release 1, Win64.

Your solutions will be compiled using the following command line: g++ -Wall -Wextra -Wconversion -static -DONLINE_JUDGE -Wl,--stack=268435456 -O2 -std=c++23 program.cpp -lstdc++exp.

Now you can start using C++23 features!

Please note that support for GNU G++23 14.2 (64 bit, winlibs) is currently experimental. We invite you to join in the testing and experimentation process. Share your thoughts and experiences in the comments!

UPD 1: It seems this distribution experiences performance degradation, which can lead to time limit exceeded verdict in some cases. For now, we don't recommend using it in real contests.

UPD 2: I figured out how to make the print function work. The compilation line has been changed, and it now works.

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25 hours ago, # |
  Vote: I like it 0 Vote: I do not like it

Cool

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25 hours ago, # |
  Vote: I like it +62 Vote: I do not like it

clang diag when back

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25 hours ago, # |
  Vote: I like it 0 Vote: I do not like it

ha?

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25 hours ago, # |
  Vote: I like it 0 Vote: I do not like it

Finally the wait is over...[Hooray]

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25 hours ago, # |
  Vote: I like it +51 Vote: I do not like it

That's great! Thanks a lot!

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25 hours ago, # |
  Vote: I like it -20 Vote: I do not like it

first comment hooray!!! attractors

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25 hours ago, # |
← Rev. 4   Vote: I like it 0 Vote: I do not like it

I'd just tried to use new compiler in this submission 277680488, got TLE

but previously absolutely same solution 277680737 (1 char difference to be able to submit it again) gave me AC

MikeMirzayanov please pay attention on it

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24 hours ago, # |
  Vote: I like it +18 Vote: I do not like it

Cant use print :(

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    23 hours ago, # ^ |
      Vote: I like it +2 Vote: I do not like it

    You can refer to this.

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    14 hours ago, # ^ |
    ← Rev. 2   Vote: I like it -7 Vote: I do not like it

    Try this?

    #include <cstdio>
#include <format>

#define println(...) puts(std::format(__VA_ARGS__).c_str())

int main()
{
    println("Hello {} {}", "World", "!");
    println("Hello {:.2f}", 3.1415);
}

    And this should work in C++20.

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24 hours ago, # |
  Vote: I like it +37 Vote: I do not like it

Savior-of-Cross bro can finally rest after asking from last 5 months.

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24 hours ago, # |
  Vote: I like it +1 Vote: I do not like it

Oh finally!, it is amazing, thanks a lot!!!

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23 hours ago, # |
  Vote: I like it +3 Vote: I do not like it

Thank you.

std::format will be very useful to make many output statements cleaner for those not using printf style format strings.

Before: std::cout << a << " + " << b << " = " << a+b << '\n';

After: std::cout << std::format("{} + {} = {}\n", a, b, a+b);

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    21 hour(s) ago, # ^ |
      Vote: I like it +5 Vote: I do not like it

    Isn't std::format a C++20 feature?

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      21 hour(s) ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      Yes, I thought that it didn't work on Codeforces C++20 but I just tried it and it works already. So instead I should have mentioned std::print and std::println which are simply shortcuts for outputting std::format. My bad.

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23 hours ago, # |
← Rev. 2   Vote: I like it +25 Vote: I do not like it

Quick benchmarking got really weird: an $$$\mathcal{O}(n \log^2{n})$$$ code on 1991C - Absolute Zero used like double runtime in C++23 compared to C++20:

Was it a bug, or was it intended that way...?

Extra: trying to use set in that approach yielded 1500ms for C++20 (TL=2s), and instant TLE for C++23.

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    23 hours ago, # ^ |
    ← Rev. 2   Vote: I like it +1 Vote: I do not like it

    Extra #2: The runtime difference is seven-fold for $$$\mathcal{O}(n \log{n})$$$ ? [more precisely, $$$\mathcal{O}(n \log{\left( \max{a_i} - \min{a_i} \right)})$$$ ]

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    20 hours ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    Screenshot-2024-08-23-02190234

    Same code but different compiler versions, Solutions: C++20 and C++23 . The submission by C++20 was noticeably faster.

    I used unordered_map, i though C++23 will execute it faster but ... :)

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    15 hours ago, # ^ |
      Vote: I like it +3 Vote: I do not like it

    I compared generated code with previous version of the compiler (gcc13-64-winlibs) and it looks like new version uses very conservative set of CPU instructions. Trying to force SSE/AVX resulted in compilation failure inside of one of the STL headers.

    > g++ -Wall -Wextra -Wconversion -static -DONLINE_JUDGE -Wl,--stack=268435456 -O2 -std=c++23 -g -msse code.cpp
...
In file included from C:/Programs/gcc14-64-winlibs/include/c++/14.2.0/string:43,
                 from C:/Programs/gcc14-64-winlibs/include/c++/14.2.0/bitset:52,
                 from C:/Programs/gcc14-64-winlibs/include/c++/14.2.0/x86_64-w64-mingw32/bits/stdc++.h:52,
                 from code.cpp:5:
C:/Programs/gcc14-64-winlibs/include/c++/14.2.0/bits/allocator.h: In destructor 'constexpr std::_Vector_base<int, std::allocator<int> >::_Vector_impl::~_Vector_impl()':
C:/Programs/gcc14-64-winlibs/include/c++/14.2.0/bits/allocator.h:182:7: error: inlining failed in call to 'always_inline' 'constexpr std::allocator< <template-parameter-1-1> >::~allocator() noexcept [with _Tp = int]': target specific option mismatch
  182 |       ~allocator() _GLIBCXX_NOTHROW { }
      |       ^
In file included from C:/Programs/gcc14-64-winlibs/include/c++/14.2.0/vector:66,
                 from C:/Programs/gcc14-64-winlibs/include/c++/14.2.0/functional:64,
                 from C:/Programs/gcc14-64-winlibs/include/c++/14.2.0/x86_64-w64-mingw32/bits/stdc++.h:53:
C:/Programs/gcc14-64-winlibs/include/c++/14.2.0/bits/stl_vector.h:132:14: note: called from here
  132 |       struct _Vector_impl
      |              ^~~~~~~~~~~~
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      14 hours ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      IIRC for Codeforces GCC13-64-winlibs already experienced failures when forcing SSE/AVX to vectors, so it's not something of novelty for GCC14 in this case.

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23 hours ago, # |
  Vote: I like it +55 Vote: I do not like it

As of now, C++23 is not in the best shape, but when GCC will finally implement it, it will go hard.

Mainly for competitive programming, a C++23 gold nugget is std::print.

Finally clunky output with std::cout goes away in favor of elegant:

std::println("The meaning of the {} is {}", "universe" 42); // prints "The meaning of the universe is 42"

"Oh, nice printing, cool" you might think, but it gets better:

std::vector<std::pair<int, std::string>> vec = { {0, "hii"}, {1, "arul"} };
std::print("{}", vec); // prints [(0, "hii"), (1, "arul")]
// or not, they are not implemented yet :p
  • It is faster than std::cout or printf (so maybe fast io hack won't be as used)

Also additional cool things are std::flat_set and std::flat_map that are basically(very roughly speaking) more cache-friendly counterparts of std::set and std::map. Will it be better than std::set and std::map for competitive programming? Time will tell, right now they are not even implemented in GCC.

Also there's deducing this which makes recursive lambdas not as weird (i am a certified lambda glazer, which means that deducing this is epic and cool)

Summarizing, C++23 adds great features for competitive programming. In theory. In reality, GCC 14.2 doesn't implement most features that folks on codeforces would find interesting

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    21 hour(s) ago, # ^ |
      Vote: I like it +6 Vote: I do not like it

    It is faster than std::cout or printf (so maybe fast io hack won't be as used)

    As someone that has played around a ton with fastIO stuff in the past, I really doubt that this claim is true. Nothing low-level has fundamentally changed. The bottleneck is still the same.

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      12 hours ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      By "fast IO hack" I meant ios_base::bla_bla_bla(false) stuff almost everyone has. Didn't mean to say that it will be better than monstrous IO templates some folks use. But fmt::print is faster than my regular way of printing out stuff, so I can keep hoping

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    20 hours ago, # ^ |
      Vote: I like it +35 Vote: I do not like it

    flat_map and flat_set are essentially sorted lists, so they have linear insertion time. They're not replacements for map or set.

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      12 hours ago, # ^ |
        Vote: I like it +15 Vote: I do not like it

      oh damn, I am sorry for misinformation then :(

      when i was reading some site, it said "slower insert and delete" and I thought "Oh, so worse constant, right? Right?". Again, my apologies!

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22 hours ago, # |
  Vote: I like it +1 Vote: I do not like it

Amazing! No more cout (=

Thank you very much for the effort put into making c++23 available!

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21 hour(s) ago, # |
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Thanks a lot!!!!!

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21 hour(s) ago, # |
  Vote: I like it +7 Vote: I do not like it

genuine question: why are we naming it G++23, not C++23?

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    20 hours ago, # ^ |
      Vote: I like it +32 Vote: I do not like it

    G++ specifies that it is the gnu compiler for c++. It's always been named like that for codeforces. It's similar to how theres python and pypy to choose from, even though they're both python. I remember you could also choose clang so it makes sense for them to differentiate between the two. Idk why clang isnt a compiler option anymore though.

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    8 hours ago, # ^ |
      Vote: I like it -8 Vote: I do not like it

    G++23 is GNU version of c++ compiler which supports C++23, C++23 is the C++ standard published in 2023.

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21 hour(s) ago, # |
  Vote: I like it 0 Vote: I do not like it

Unexpected news. But thanks!

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20 hours ago, # |
← Rev. 2   Vote: I like it 0 Vote: I do not like it

Screenshot-2024-08-23-02190234

I encountered a significant difference in execution time between two submissions that used the same code but different compiler versions, Solutions: C++20 and C++23 . The submission by C++20 was noticeably faster.

Why C++23 is slower in my case???

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20 hours ago, # |
  Vote: I like it 0 Vote: I do not like it

is there any plan on update on GCC? C11 5.10 is quite outdated imo

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18 hours ago, # |
← Rev. 3   Vote: I like it +9 Vote: I do not like it

Wow! Is std::print available now?

Also, is codeforces the first onlinejudge which have GCC14?

Update: Emm, seems there are still some problems with std::print. :(

Update 2: Now the problems with std::print is fixed, thanks Mike. :)

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17 hours ago, # |
  Vote: I like it +54 Vote: I do not like it

Thanks

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17 hours ago, # |
  Vote: I like it +1 Vote: I do not like it

Cool update,but hope MikeMirzayanov can notice this about C[loud]F[are] we concerned about.

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16 hours ago, # |
  Vote: I like it 0 Vote: I do not like it

Finally, it happened.

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16 hours ago, # |
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auto!

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15 hours ago, # |
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when zig? when nim?

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15 hours ago, # |
  Vote: I like it +60 Vote: I do not like it

Please upgrade to 14.3 when it releases, dynamic_bitset is fixed in that version.

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15 hours ago, # |
  Vote: I like it 0 Vote: I do not like it

Thrilled to see G++23 now supported on Codeforces! Ready to leverage the latest C++ features. <3

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15 hours ago, # |
  Vote: I like it 0 Vote: I do not like it

COOOOOL! Does c++23 have constant optimization for stl or pbds?

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14 hours ago, # |
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Thats great but how can i find the new features of c++23?

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13 hours ago, # |
  Vote: I like it 0 Vote: I do not like it

Is the support for C++23 features incomplete in this compiler version? For example, is print still not usable. The following code will result in compilation errors:

#include <print>
#include <string>
#include <vector>

int main()
{
	std::string val = "hello";
	std::print("{}", val);
}
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13 hours ago, # |
  Vote: I like it +6 Vote: I do not like it

Cool LOL

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12 hours ago, # |
  Vote: I like it +8 Vote: I do not like it

After 40 years, c++ finally has print() function

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11 hours ago, # |
← Rev. 2   Vote: I like it +6 Vote: I do not like it

It seems slow, and not able to use std::print and std::println for now

UPD: Thank to mike that std::print and std::println are available.

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    9 hours ago, # ^ |
      Vote: I like it +6 Vote: I do not like it

    I fixed the print issue, but performance is still poor in some cases.

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9 hours ago, # |
  Vote: I like it 0 Vote: I do not like it

If you are getting errors like parsing errors or missing arguments, it is because the powershell is recognizing ',' as some special charachter.

Try this instead in that case:

g++ -std=c++23 -Wall -Wextra -Wconversion -static -DONLINE_JUDGE -Xlinker --stack=268435456 -O2 .\program.cpp

to compile the file, and since any name is not given in, the exe should be names to a.exe or something similar by default, and you can run that file by

.\a

Or, if you are an only-IDE person

All along, your code for compiling and running altogether will be

cd "PATH_TO_YOUR_WORKING_DIRECTORY" ; if ($$$?) { g++ -std=c++23 -Wall -Wextra -Wconversion -static -DONLINE_JUDGE -Xlinker --stack=268435456 -O2 .\program.cpp } ; if ($$$?) { .\a }

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    8 hours ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    Just quote -Wl,--stack=268435456. In vscode + code runner, it is like:

    "cpp": "cd $dir && g++ --std=c++23 -Wall -Wextra -Wconversion -static \"-Wl,--stack=268435456\" -O2 $fileName -o $fileNameWithoutExt && $dir$fileNameWithoutExt"

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8 hours ago, # |
  Vote: I like it 0 Vote: I do not like it

after using that command it still shows that gcc version is 13.2.0

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C:\ProgramData\pbox\temp\65617\gcc14-64-winlibs$14.2.0-1>rd /S /Q gcc14-64-winlibs INFO [2024-08-23 14:52:28,631] Set environment variable 'GCC_14_64_WINLIBS_HOME=C:\Programs\gcc14-64-winlibs'. INFO [2024-08-23 14:52:28,631] Starting 'setx.exe GCC_14_64_WINLIBS_HOME C:\Programs\gcc14-64-winlibs /M'. INFO [2024-08-23 14:52:33,509] Successfully set environment variable 'GCC_14_64_WINLIBS_HOME=C:\Programs\gcc14-64-winlibs'. INFO [2024-08-23 14:52:40,241] Package 'gcc14-64-winlibs$14.2.0-1' installed to the 'C:\Programs\gcc14-64-winlibs'.

C:\Windows\System32>gcc --version gcc (MinGW-W64 x86_64-ucrt-mcf-seh, built by Brecht Sanders, r3) 13.2.0 Copyright (C) 2023 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

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    8 hours ago, # ^ |
      Vote: I like it +3 Vote: I do not like it

    I installed via pbox as suggested and in my case it is fine:

    C:\Programs\gcc14-64-winlibs\bin>gcc --version
gcc (MinGW-W64 x86_64-ucrt-posix-seh, built by Brecht Sanders, r1) 14.2.0
Copyright (C) 2024 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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    5 hours ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    Restart cmd session to reload environment variables. Also check your PATH variable for another gcc before this.

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5 hours ago, # |
← Rev. 2   Vote: I like it 0 Vote: I do not like it

G++23 may cause some magical RE.

Submission using G++23: RE on #1 277773823

Submission using G++20: Accepted 277773900

UPD: Solved, I reversed the order

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