The Gray Code Decoder and Gray Code Encoder holes will go live in approximately 32 hours. Why not try and solve them ahead of time?
Fibonacci in C in chars. Achievements Cheevos Holes Languages Medals Miscellaneous All Holes 12 Days of Christmas 24 Game 99 Bottles of Beer Abundant Numbers Abundant Numbers (Long) Arabic to Roman Arithmetic Numbers Arrows Ascending Primes ASCII Table Billiards brainfuck Calendar Card Number Validation Catalan Numbers Catalan’s Constant Christmas Trees Collatz Continued Fractions CSS Colors Cubes Day of Week DFA Simulator Diamonds Divisors Emirp Numbers Emirp Numbers (Long) Emojify Evil Numbers Evil Numbers (Long) Factorial Factorisation Farey Sequence Fibonacci Fizz Buzz Foo Fizz Buzz Bar Forsyth–Edwards Notation Fractions Game of Life Gijswijt’s Sequence Happy Numbers Happy Numbers (Long) Hexdump Hilbert Curve Intersection Inventory Sequence ISBN Jacobi Symbol Kaprekar Numbers Kolakoski Constant Kolakoski Sequence Leap Years Levenshtein Distance Leyland Numbers ln 2 Look and Say Lucky Numbers Lucky Tickets Mahjong Mandelbrot Maze Medal Tally Minesweeper Morse Decoder Morse Encoder Multitap Input Musical Chords N Queens Niven Numbers Niven Numbers (Long) Number Spiral Odious Numbers Odious Numbers (Long) Ordinal Numbers PalindromemordnilaP Pangram Grep Partition Numbers Pascal’s Triangle Pernicious Numbers Pernicious Numbers (Long) Poker Polyominoes Prime Numbers Prime Numbers (Long) Proximity Grid QR Decoder Quine Recamán Repeating Decimals Reverse Polish Notation Reversi Rijndael S-box Rock-paper-scissors-Spock-lizard Roman to Arabic ROT13 Rule 110 Scrambled Sort Set Seven Segment SI Units Sierpiński Triangle Smith Numbers Spelling Numbers Star Wars GPT Star Wars Opening Crawl Sudoku Sudoku (Fill-in) Ten-pin Bowling Tic-tac-toe Time Distance Tongue-twisters Topological Sort Tower of Hanoi Transpose Sentence Trinomial Triangle United States Vampire Numbers Van Eck Sequence Zeckendorf Representation Zodiac Signs γ λ π τ φ √2 𝑒 Alphabetic Numbers Apéry’s Constant Binary Lambda Calculus Connect Four Crossword CSS Colors (Inverse) CSS Grid Ellipse Perimeters Flags Floyd-Steinberg Dithering Gray Code Decoder Gray Code Encoder Hexagonal Spiral Highly Composite Numbers NFA Simulator Numbrix Odd Polyomino Tiling p-adic Expansion Polygon Triangulations QR Encoder Quadratic Formula Rectangle Fill Semiprime Numbers Smooth Numbers Snake Sphenic Numbers Taxicab Numbers Turtle Tutorial All Languages ><> ALGOL 68 ArkScript Assembly AWK Bash BASIC Berry brainfuck C C# C++ Civet Clojure COBOL Coconut Common Lisp Crystal D Dart Elixir Erlang F# Factor Forth Fortran Gleam Go GolfScript Groovy Haskell Hexagony J Janet Java JavaScript jq Julia K Kotlin Lua Nim OCaml Pascal Perl PHP PowerShell Prolog Python R Raku Rockstar Ruby Rust Scheme sed SQL Swift Tcl TeX V VimL Wren Zig 05AB1E APL Arturo Befunge BQN CJam CoffeeScript Egel Fennel Harbour Hare Haxe Hush Hy iogii Knight Lily Luau Odin Picat Qore Racket Rebol Rexx Scala Squirrel Stax Uiua Umka Vala Vyxal Bytes Chars Scoring Bytes Chars Language All ><> ALGOL 68 ArkScript Assembly AWK Bash BASIC Berry brainfuck C C# C++ Civet Clojure COBOL Coconut Common Lisp Crystal D Dart Elixir Erlang F# Factor Forth Fortran Gleam Go GolfScript Groovy Haskell Hexagony J Janet Java JavaScript jq Julia K Kotlin Lua Nim OCaml Pascal Perl PHP PowerShell Prolog Python R Raku Rockstar Ruby Rust Scheme sed SQL Swift Tcl TeX V VimL Wren Zig Experimental Language 05AB1E APL Arturo Befunge BQN CJam CoffeeScript Egel Fennel Harbour Hare Haxe Hush Hy iogii Knight Lily Luau Odin Picat Qore Racket Rebol Rexx Scala Squirrel Stax Uiua Umka Vala Vyxal Hole All 12 Days of Christmas 24 Game 99 Bottles of Beer Abundant Numbers Abundant Numbers (Long) Arabic to Roman Arithmetic Numbers Arrows Ascending Primes ASCII Table Billiards brainfuck Calendar Card Number Validation Catalan Numbers Catalan’s Constant Christmas Trees Collatz Continued Fractions CSS Colors Cubes Day of Week DFA Simulator Diamonds Divisors Emirp Numbers Emirp Numbers (Long) Emojify Evil Numbers Evil Numbers (Long) Factorial Factorisation Farey Sequence Fibonacci Fizz Buzz Foo Fizz Buzz Bar Forsyth–Edwards Notation Fractions Game of Life Gijswijt’s Sequence Happy Numbers Happy Numbers (Long) Hexdump Hilbert Curve Intersection Inventory Sequence ISBN Jacobi Symbol Kaprekar Numbers Kolakoski Constant Kolakoski Sequence Leap Years Levenshtein Distance Leyland Numbers ln 2 Look and Say Lucky Numbers Lucky Tickets Mahjong Mandelbrot Maze Medal Tally Minesweeper Morse Decoder Morse Encoder Multitap Input Musical Chords N Queens Niven Numbers Niven Numbers (Long) Number Spiral Odious Numbers Odious Numbers (Long) Ordinal Numbers PalindromemordnilaP Pangram Grep Partition Numbers Pascal’s Triangle Pernicious Numbers Pernicious Numbers (Long) Poker Polyominoes Prime Numbers Prime Numbers (Long) Proximity Grid QR Decoder Quine Recamán Repeating Decimals Reverse Polish Notation Reversi Rijndael S-box Rock-paper-scissors-Spock-lizard Roman to Arabic ROT13 Rule 110 Scrambled Sort Set Seven Segment SI Units Sierpiński Triangle Smith Numbers Spelling Numbers Star Wars GPT Star Wars Opening Crawl Sudoku Sudoku (Fill-in) Ten-pin Bowling Tic-tac-toe Time Distance Tongue-twisters Topological Sort Tower of Hanoi Transpose Sentence Trinomial Triangle United States Vampire Numbers Van Eck Sequence Zeckendorf Representation Zodiac Signs γ λ π τ φ √2 𝑒 Experimental Hole Alphabetic Numbers Apéry’s Constant Binary Lambda Calculus Connect Four Crossword CSS Colors (Inverse) CSS Grid Ellipse Perimeters Flags Floyd-Steinberg Dithering Gray Code Decoder Gray Code Encoder Hexagonal Spiral Highly Composite Numbers NFA Simulator Numbrix Odd Polyomino Tiling p-adic Expansion Polygon Triangulations QR Encoder Quadratic Formula Rectangle Fill Semiprime Numbers Smooth Numbers Snake Sphenic Numbers Taxicab Numbers Turtle Tutorial # Golfer Points Chars Time Submitted 393rd muser-logiccpu 🇺🇦 682 66 1ms 21 Aug 2025 402nd asadullayev 672 67 1ms 9 Dec 2020 402nd godraadam 672 67 1ms 13 Apr 2021 402nd Xwilarg 🇫🇷 672 67 1ms 17 Nov 2021 402nd michatmon 672 67 2ms 11 Jan 2022 402nd martinnorling 🇸🇪 672 67 1ms 8 Feb 2022 402nd JasonRaubenheimer 672 67 1ms 8 Jul 2023 402nd jtaxen 672 67 1ms 26 Apr 2024 402nd CutSandstone 672 67 1ms 5 Jul 2024 410th pingu19 662 68 1ms 16 Oct 2019 410th mxchen2001 662 68 1ms 18 Nov 2020 410th LeeCamp 662 68 1ms 28 Apr 2022 410th esseeffeenne 662 68 1ms 6 Jun 2022 410th GameChaos 662 68 1ms 16 Jun 2022 415th TornadoCookie 652 69 1ms 17 Oct 2022 415th xnacly 🇩🇪 652 69 1ms 30 Jun 2023 415th Pyro569 652 69 1ms 30 Jul 2023 415th eiburns 652 69 1ms 7 Sep 2023 415th viitanet 652 69 1ms 22 Oct 2023 415th hacker112 🇸🇪 652 69 1ms 12 Jun 2024 415th msbranicky 652 69 2ms 3 Jul 2024 415th SwordF-Official 🇺🇸 652 69 1ms 3 Jun 2025 415th Alex-Huggett 🇬🇧 652 69 2ms 13 Sep 2025 415th zgialor-lab 652 69 2ms 17 Dec 2025 425th PatrickLove 643 70 1ms 26 Jun 2019 425th furokku 643 70 1ms 14 Feb 2021 425th gabe-gallegos 643 70 2ms 25 Mar 2025 425th RYSF13 🇨🇳 643 70 2ms 19 Jul 2025 429th chunky 634 71 1ms 2 Oct 2020 429th jackrosenb 634 71 1ms 7 Oct 2020 429th Lizard314 634 71 1ms 10 Nov 2020 429th yoshykai 634 71 1ms 16 Jun 2023 429th jccummi1 634 71 1ms 29 Oct 2023 429th LawrenceZ1A 🇨🇦 634 71 1ms 25 Feb 2024 429th nstearns96 🇬🇧 634 71 2ms 13 Sep 2024 436th kendstott 625 72 1ms 25 Jun 2019 436th kirbyyourmom 🇬🇧 625 72 2ms 2 Mar 2021 436th mqyhlkahu 625 72 1ms 10 Sep 2023 436th 0dyse 625 72 2ms 6 May 2025 440th DrProfPatPending 616 73 1ms 25 Jun 2019 440th nwdamgaard 616 73 2ms 19 Dec 2021 442nd willpiam 608 74 1ms 21 Sep 2021 442nd dillon-duncando 608 74 2ms 24 Dec 2021 442nd Vexxter9 🇳🇱 608 74 1ms 20 Sep 2024 445th KiwiKoder0123 600 75 1ms 28 Jun 2019 445th StHagel 600 75 1ms 25 May 2023 445th Azearia 600 75 1ms 9 Aug 2023 445th NDR0216 🇹🇼 600 75 11ms 8 May 2024 445th RedzGoose 🇦🇺 600 75 1ms 19 Sep 2024 445th Sciman101 600 75 2ms 26 Mar 2025 451st HectorPeeters 592 76 11ms 26 Mar 2021 451st opsiff 592 76 2ms 8 Aug 2021 451st iwalker2702 592 76 2ms 9 Nov 2021 451st GreenBeansAgainstVeganism 592 76 11ms 28 May 2022 451st james-downey 592 76 11ms 14 Jul 2022 451st DaCuteRaccoon 592 76 1ms 12 Dec 2022 451st NeatCrown 🇨🇦 592 76 2ms 14 Dec 2022 451st tvcv901 592 76 10ms 22 Mar 2023 451st hjcafaroUC 592 76 2ms 5 Aug 2023 451st ridingqwerty 🇺🇸 592 76 11ms 21 Dec 2023 461st ramytarchichy 584 77 12ms 22 Jun 2019 461st EnergeticBark 584 77 2ms 14 Jul 2019 461st jngbsn 584 77 1ms 30 Jun 2020 461st ei14 584 77 11ms 23 Jun 2021 461st mickmurci 584 77 12ms 7 Apr 2023 461st IdkWhatIsIdk 584 77 1ms 27 Nov 2024 467th DeepuBenson 577 78 1ms 27 Mar 2020 467th dev-loop0 577 78 1ms 20 Aug 2020 467th oschmidh 577 78 11ms 18 Nov 2020 467th muztanger 577 78 2ms 1 Jan 2021 467th 444nuits 577 78 12ms 31 Jan 2022 467th junten1 577 78 1ms 18 Oct 2024 473rd davidgblanes 570 79 1ms 22 Sep 2019 473rd SiBeepBoop 570 79 17ms 14 Apr 2025 473rd axvonx 570 79 12ms 21 Jan 2026 473rd RodAlc24 🇪🇸 570 79 2ms 21 Feb 2026 477th volpi-m 🇫🇷 563 80 1ms 30 Aug 2020 477th denballakh 563 80 1ms 25 Nov 2021 477th Adix-null 🇱🇹 563 80 2ms 4 Jul 2023 477th StupidHobbit 563 80 2ms 25 Nov 2025 First Prev 401–480 of 603 Next Last