Challenges
Dive into our coding challenges to have fun and acquire new skills. Join us in chat to discuss!
NEW! Grow your skills
Challenges offer an easy way to test your understanding and pick up some additional skills along the way.
Add your entry to the challenge
Put your coding skills to the test and share your answer with everyone. We're excited to see what you've come up with.
Time to discuss and vote
Explore the diverse solutions from our community. Share your thoughts through comments, ask questions, and appreciate great code by casting your vote for the best entry.
And the awards go to...
Your brilliant solutions earn you special recognition! We'll be highlighting top contributors and insightful approaches, so put your best code forward.
Challenge 20: We all scream for Ice Cream!
The Challenge: Write a program to determine how many tubs of various ice cream flavors a volunteer needs to purchase for an ice cream social fundraiser she is planning for a charity organization. 30 ...
- reputation score 1488
Challenge #19: In Other Words... [COMPLETED]
Update on June 17: This challenge is now closed, thanks to everyone who gave it a shot. The winners of this challenge are: André, Apfelvater, Daniel T, Fred Bill, Jannik S., joaocandre, Kane ...
- reputation score 1
Challenge #18: Hidden in Plain Sight [COMPLETED]
Update on May 14, 2026: This challenge is now closed, thanks to everyone who participated. The winners of this challenge are: AKHolland, amance, Aravind K. B, Book, cknott, Daniel T, Dmitrii Bychenko, ...
- reputation score 2306
Challenge #17: The Accurate Selection [COMPLETED]
Update on April 14, 2026: This challenge is now closed. Thanks to everyone who participated! The winners of this challenge, who solved all 10 selections, are: Atmo, cknott, keymasterr, Antoine, ...
Challenge #16: Change is the only constant [COMPLETED]
Update on March 12, 2026: Thanks to everyone who participated in Challenge 16! The correct output is: 73, -1, 6, -1, 4, 2, -1, 5, 2, -1, 5, 2, 3, -1, 2, 4, 4, 2, 2, 2, 4, 4, 3, 2, 3, 2, 4, 3, 3, 4, 3, ...
Challenge #15: Mystery Alphabet Decoder [COMPLETED]
Update on February 13, 2026: Thanks to everyone who participated in Challenge 15! The correct output for the alien alphabet is: ⪏⊚⊕⊟⊞⨙⊛∫∫∫↔⊠⊝৲⊣⊗⇲⊥⊢◉⊡⊤◴⚆⊜↪ 87 users got the right answer, out of 101 ...
Challenge #14: Signal from Noise [COMPLETED]
Update on January 8, 2026: Huge thanks to everyone who participated in the challenge. The conditions for signal/noise were tricky, and we appreciate the careful implementations! The correct sum of the ...
- reputation score 179
Challenge #13: Integer sorting in a grid [COMPLETED]
Update on October Dec 4: Huge thanks to everyone who participated in the challenge. The correct answer is that 45 of the sets were impossible to put into the grid. We received 70 responses from 68 ...
Challenge #12: Spooky Halloween scene [COMPLETED]
Update, Nov 13: Thanks to all that participated and voted in this challenge! In terms of votes, top 3 entries were: 1st place: Phil with a spooky house scene 2nd place: Death-is-the-real-truth (...
Challenge #11: Taco crawl optimization [COMPLETED]
Update on October 23: Huge thanks to everyone who participated in the challenge. The correct routing was [0,7,5,6,2,10,4] for 97 tastiness and 2.8945 tastiness/distance. 43 of the 53 entries provided ...
- reputation score 1
Challenge #10: Road safety challenge (joint with Kaggle) [COMPLETED]
Update, Nov 1, 2025: The challenge is now complete. Thanks to those that participated. We'll review the entries and soon announce the users that receive the badge. Kaggle is a platform for Machine ...
- reputation score 1
Challenge #9: Random Number Generator [COMPLETED]
Update: October 6, 2025: Thanks to everyone who participated in this challenge! It was very interesting to see the diverse approaches to random number generation. Congratulations to the following ...
- reputation score 1
Challenge #8: Word ladder [COMPLETED]
Update, October 2, 2025: Appreciation to everyone who participated in this challenge! The correct length of the word ladders is as follows: [stone, money] [11] [bread, crumb] [11] [smile, giant] [11] ...
- reputation score 1
Challenge #7: Pangram checker [COMPLETED]
Update, October 2, 2025: A HUGE thanks to everyone who participated in this challenge! The correct answer is: 819 Non-Pangrams, 132 Pangrams (non-perfect) and 49 Perfect-Pangrams. We are very ...
Challenge #6: Integer Counting [COMPLETED]
Update on October 8, 2025: Thanks to everyone who voted on the entries! We received 281 votes from 59 users. There were a lot of great responses to this challenge. We appreciate the participation. We'...
- reputation score 1
Challenge #5: Traffic Light Simulator [COMPLETED]
Congratulations to Kamran for the best response to this challenge! We were impressed by your simulation and also the inclusion of variable weather elements. This Challenge is now closed but entries ...
- reputation score 35735
Challenges Sandbox – Help us create new challenges
We are making some upgrades to Challenges – one of which is allowing users to contribute their own! If you have an idea for a challenge, please post it as an entry here in this Sandbox, where it can ...
Challenge #4: Create a futuristic technology [COMPLETED]
Awards for the fourth Stack Overflow code challenge: Most Upvotes: Davide Fiocco Vision Architect: 12Kittens New Contributor: Prakhar Agarwal All of the awards given (aside from most upvotes) are ...
- reputation score 1
Challenge #3: Creating ASCII art snowflakes [COMPLETED]
Awards for the third Stack Overflow code challenge: Most Upvotes: André Serene Scene Creator: Ale_Bianco New Contributor: Michael Brown Most Customizable: FoxWise Snowflake Artisan: Newpzo All of the ...
Challenge #2: Secret messages in game boards [COMPLETED]
Awards for the second Stack Overflow code challenge: Most upvotes: Ale_Bianco Puzzle prodigy: Anon Coward New contributor: Ayan Nayak Most imaginative: Bladeski Straight to the point: NullDev All of ...
- reputation score 1
Challenge #1: Implement a text-to-baby-talk translator [COMPLETED]
Awards for the first Stack Overflow code challenge: Most upvotes: Anon Coward Bells and whistles: Ali Sheikhpour New contributor: Kingsley_3z3nw4k4 Most sophisticated: return true Technically correct: ...
- reputation score 31439