The Gray Code Decoder and Gray Code Encoder holes will go live in approximately 6 days. Why not try and solve them ahead of time?
Card Number Validation in all languages in bytes. 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 Bytes Time Submitted 561st Yax42 🇫🇷 654 108 2ms 29 hours ago 562nd chartung17 654 122 10ms 24 Mar 2025 563rd w911 651 183 281ms 7 Oct 2024 564th albanian-laundromat 651 293 14ms 8 Dec 2025 565th Babafaba 650 102 530ms 11 Nov 2025 566th emgordon154 650 111 4ms 12 Jan 2025 567th rucin93 🇵🇱 649 144 156ms 28 Oct 2024 568th DialFrost 🇸🇬 648 67 2ms 22 Dec 2024 569th msbranicky 648 123 16ms 3 Oct 2024 569th bobbysq 648 123 11ms 5 Oct 2024 569th wuzekai518 648 123 10ms 8 Oct 2024 569th denkyuu1 648 123 17ms 15 days ago 573rd koipondx86 645 123 2ms 8 Nov 2024 574th frankgraziano 645 128 7ms 21 Feb 2026 575th CaedenHarper 🇨🇦 644 100 10ms 22 Aug 2025 575th iczelia 🇩🇪 644 100 11ms 11 Oct 2025 575th Yax42 🇫🇷 644 100 11ms 27 Nov 2025 578th Apataras 644 145 390ms 25 Jun 2025 579th tomh1012 643 111 500ms 8 Sep 2025 580th NotEvenIndian 643 124 10ms 22 Oct 2024 580th ridingqwerty 🇺🇸 643 124 16ms 16 Jan 2025 580th CommandLeo 🇮🇹 643 124 10ms 5 Oct 2025 580th JOrE20 643 124 17ms 21 Feb 2026 584th Jonatan6 🇩🇰 642 110 2ms 24 Oct 2024 585th elgan65536 🇺🇸 640 146 161ms 2 Oct 2024 585th dokutan 640 146 379ms 23 Nov 2025 585th luuumine 🇫🇷 640 146 159ms 26 Nov 2025 588th stefangimmillaro 639 73 314ms 1 Oct 2024 589th MeWhenI 🇻🇦 638 73 7ms 3 Oct 2024 590th bnic24 638 125 16ms 3 Oct 2024 590th adoxography 638 125 11ms 22 Oct 2024 590th wh3n3v3r 🇨🇿 638 125 10ms 18 Nov 2024 590th lelbal 638 125 10ms 14 Oct 2025 594th MeWhenI 🇻🇦 634 91 994ms 29 Aug 2025 595th msbranicky 634 188 301ms 7 Jan 2025 596th XenThe 🇬🇧 632 102 10ms 7 Jul 2025 596th Florian-Mt 632 102 11ms 5 Dec 2025 598th KatieLG 🇬🇧 632 105 439ms 11 Feb 2026 599th Shanethegamer 🇺🇸 631 74 324ms 16 Oct 2024 600th albanian-laundromat 631 264 1,429ms 3 Nov 2025 601st CatsAreFluffy 628 127 17ms 30 Oct 2024 601st WillowWispy 628 127 11ms 25 May 2025 603rd DialFrost 🇸🇬 627 304 153ms 13 Aug 2025 604th AlephSquirrel 625 40 44ms 1 Oct 2024 605th not-a-pokemon 625 113 1ms 23 Jul 2025 606th dokutan 624 127 2ms 10 Dec 2024 607th BalaM314 620 104 11ms 4 Feb 2025 607th acollett89 620 104 10ms 15 Jul 2025 609th HumanoidCPU 620 107 502ms 17 Feb 2025 610th codereport 🇨🇦 619 63 33ms 2 Oct 2024 611th jupj 🇫🇮 619 114 2ms 20 Jul 2025 612th MarcMush 🇫🇷 618 91 813ms 8 Oct 2024 613th madex 🇩🇪 618 129 16ms 2 Oct 2024 613th RedzGoose 🇦🇺 618 129 11ms 15 Oct 2024 613th calebaitken 618 129 10ms 11 Apr 2025 613th rollershutter 618 129 17ms 20 Nov 2025 617th Ripick 617 135 366ms 23 Mar 2025 618th bac0id 616 141 487ms 10 Jan 2025 619th Europe2048 613 130 10ms 2 Oct 2024 619th nstearns96 🇬🇧 613 130 17ms 2 Oct 2024 619th Stockoh 🇫🇷 613 130 17ms 4 Jul 2025 622nd evnu 612 147 87ms 12 Oct 2025 623rd Seanharrs 🇦🇺 610 117 478ms 15 Nov 2024 624th inverseLorentz 🇦🇺 609 131 11ms 7 Oct 2024 624th sciencejiho 609 131 17ms 11 Feb 2025 624th Jaydosu 609 131 11ms 11 Apr 2025 624th Emutis 🇱🇹 609 131 9ms 11 Nov 2025 628th kaascevich 609 134 125ms 9 Jul 2025 629th HumanoidCPU 608 106 12ms 7 Mar 2025 629th daveberlin 608 106 10ms 27 Jun 2025 631st MeWhenI 🇻🇦 607 111 89ms 2 Oct 2024 632nd Shanethegamer 🇺🇸 607 154 156ms 3 Oct 2024 633rd emgordon154 606 156 8ms 13 Dec 2024 634th alemelis 605 93 467ms 1 Oct 2024 635th roguh 🇬🇹 604 117 1ms 13 Oct 2024 635th iczelia 🇩🇪 604 117 2ms 25 Sep 2025 637th albanian-laundromat 603 72 1ms 25 Feb 2026 638th Mabeloid 🇳🇴 600 133 11ms 2 Oct 2024 639th dokutan 598 116 2ms 19 Nov 2025 640th MeWhenI 🇻🇦 597 98 7ms 1 Oct 2024 First Prev 561–640 of 916 Next Last