2025 – The 29th IOCCC

where to start

See below for links to the 2025 winning IOCCC entries.

check it out index.html Web page for each winning entry. They have most of the information needed to compile and run a winning program. Take a look at the Winner source code and try to figure out how it works. You may also want to check out the author’s notes for more details.

You can download all the winning entries for this year’s contest as a compressed tarball.

For IOCCC29The quantity and quality of presentations was at an almost historic high.

IOCCC28 It was estimated that the 4-year absence attracted a record number of submissions, allowing authors to refine their submissions, resulting in a higher than usual quality of submissions.

IOCCC29 This was the second consecutive competition after the 2020–2024 hiatus. And yet, the number of submissions IOCCC29 The competition was similar to last year’s, and the overall presentation quality for this competition remained high. So perhaps the increased submission volume, along with higher submission quality than usual, is due to factors such as improved website design, increased social media presence, writers building on ideas from previous winning entries, and other factors?

starting from the end of IOCCC28The processes used to close the contest for new submissions, the judging process, selecting the winning entries, preparing updates to the website, and creating the live show on Our Favorite Universe were carefully documented. And while this documentation required additional time as well as more effort, the documentation process resulted in an overall improvement IOCCC is run.

A few days after the presentation of the winning entries for IOCCC29 Our Favorite Universe is created on YouTube channel. The recording of the main show will be divided into separate segments. Then, each winning entry will be updated to include a link to the YouTube segment under a new award presentation near the top of the winning entry index.html Page.

fun challenge information

We’ve added fun challenges to this year’s contest for the winning entries, underJudges’ Comments” section. After finding out what a given winning entry does, we encourage you to try the fun challenge.

Some of these challenges are easier than others. In some cases, you are asked to create an alternative version of prog.c Or any related file. In some cases you are asked to provide clarification about something.

If it’s a fun challenge still open (check “a fun challenge” section for a given winning entry), consider submitting a GitHub pull request as a contribution.

If the fun challenge is closed but you think you have a better solution, consider submitting a GitHub pull request as a contribution. If the IOCCC judges agree that your solution is better, we will consider it.

If you think you have an even better (or improved) entry to win the fun challenge, please consider submitting a GitHub pull request for the IOCCC judges’ consideration.

Rules and Guidelines of this Contest

The final versions of the IOCCC rules and guidelines in effect for this competition were:

IOCCC rules and guidelines IOCCC29 Represented a major rewrite compared to previous competitions, partly thanks to numerous volunteers: the IOCCC provided useful editing, text rewriting, consolidation, as well as overall better organization to the judges.

looking forward to the next competition

we are planning to open IOCCC30 until the end of 2026 and the competition will run for the same amount of time, ending sometime at the end of the first quarter of 2027.

As soon as we take the necessary actions to open IOCCC30We plan to document the process internally as we did during the closing IOCCC29.

When working on creating possible write-ups for submissions entering the final round of a set of judging rounds:

• Some submissions were set aside in the final round of the final set of rounds.
• We received an additional level of appreciation for many of the remaining entries.

While the winning entry writers came from the locations of previous winning writers, this IOCCC29 There was one author – jingp49 from a new location: Taiwan.

This competition saw a hat-trick of hat-tricks:

Notable and Notable Winning Entries of IOCCC29 Include, but are not limited to:

they are just a few many amazing winners of IOCCC29So be sure to check out the rest!

As we discussed above, there were some excellent submissions that didn’t make it to the final cut. We really appreciate the hard work each author put into their entries, but we regret that we can’t award awards based on effort alone.

We received many great submissions that did not make it as winners. If you submitted something for IOCCC29 He couldn’t win, think about improving his code and give him another chance
IOCCC30. Interestingly, more than one winner IOCCC29 was actually an improved version of the code that did not win the previous competition.

Incentive for those who could not win this year

We know that many of you have put a lot of effort into submitting your submissions to this year’s IOCCC. We can’t give awards to everyone. This will mean eliminating the submissions that we feel are the best and deserve to win.

Sometimes, a final round submission may be good enough to become the winning IOCCC entry, only to be defeated by a similar, but slightly better, submission. If you find that this has happened to your submission, consider submitting an improved version to the next IOCCC.

Please do not Give up hope! There are some submissions that have been submitted with revisions several times before reaching the level of the winning IOCCC entry. You may want to try with a different type of submission for the next IOCCC.

If you are not planning to improve and resubmit your non-winning entry for the next IOCCC, you are welcome to publish it.

On compiling and running winning entries

Some C compilers are not as great as they could have been. If yours is not working well, you may want to try compiling with an updated version of Clang and/or GCC instead.

If you have problems compiling and/or running winning entries, see the FAQ:

For additional information about how to submit corrections, see the FAQ:

For more information

Download all winning entries from 2025