The Gray Code Decoder and Gray Code Encoder holes will go live in approximately 3 days. Why not try and solve them ahead of time?
Card Number Validation in Python 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 159th RobGLambert 472 142 17ms 8 Jun 2025 159th GodlyProgrammer1 472 142 18ms 22 Nov 2025 159th jbjd 472 142 11ms 4 Feb 2026 164th GeneralFabian 469 143 10ms 9 Dec 2024 164th CutSandstone 469 143 10ms 30 Jan 2025 164th kistlerf 🇨🇭 469 143 17ms 19 May 2025 167th hiichbindermax 465 144 17ms 2 Oct 2024 167th mathisfun271 465 144 10ms 14 Oct 2024 167th bob-th 465 144 10ms 22 Oct 2024 170th croc54 459 146 10ms 15 Dec 2024 171st PyryL 🇫🇮 456 147 10ms 1 Mar 2025 172nd mbittner20 453 148 10ms 13 Oct 2024 172nd YAJUE114514 453 148 10ms 12 Dec 2025 174th psaban 450 149 15ms 31 Jul 2025 174th TheZwierzLF 🇵🇱 450 149 11ms 24 Nov 2025 174th RodAlc24 🇪🇸 450 149 17ms 22 Feb 2026 177th jameswmccarty 447 150 10ms 5 Oct 2024 177th yousefalizadeh 447 150 10ms 23 Oct 2024 177th feherd 447 150 11ms 31 Oct 2024 177th kadamkaustubh 447 150 10ms 8 Nov 2025 181st adamnielson42 🇺🇸 441 152 10ms 6 Oct 2024 181st voidgloom 441 152 10ms 22 Oct 2024 181st omero-san 441 152 10ms 22 Sep 2025 181st brochmann 🇸🇪 441 152 10ms 12 Oct 2025 185th denisfouchard 438 153 10ms 21 Aug 2025 186th osNiko 🇧🇷 435 154 9ms 21 Aug 2025 187th celiendonze 🇨🇭 432 155 10ms 17 Oct 2025 187th aksyristos 432 155 10ms 18 days ago 189th Shotokhan 429 156 10ms 21 Sep 2025 190th lhulinsky 427 157 10ms 21 Oct 2024 191st ellis-rix 424 158 10ms 9 Dec 2024 192nd webmiche 421 159 11ms 3 Nov 2025 193rd CheeseCake628 🇳🇴 419 160 104ms 5 Nov 2024 194th pres-abhisheksinha 416 161 10ms 8 Oct 2024 195th ibixina 414 162 11ms 13 Oct 2024 195th TheAtrossian 414 162 11ms 5 Jan 2025 197th Vaekor 406 165 11ms 15 Dec 2024 198th JesseNoEyes 🇺🇸 396 169 11ms 1 Oct 2024 199th zyc-2024 🇨🇳 394 170 10ms 5 Oct 2024 200th ComputerKWasTaken 🇺🇸 392 171 10ms 14 Oct 2024 201st navier-1 387 173 10ms 22 Sep 2025 202nd clayboll99 381 176 10ms 10 Jul 2025 203rd muser-logiccpu 🇺🇦 379 177 18ms 9 Aug 2025 204th OSYCh314 🇦🇺 376 178 10ms 2 Nov 2024 205th calum12345 372 180 10ms 26 Mar 2025 206th zt14427 368 182 11ms 27 Dec 2024 207th IoLimmer 366 183 10ms 10 Oct 2024 208th estomagordo 🇳🇱 360 186 10ms 15 Jul 2025 209th gautambp 307 218 11ms 24 Jun 2025 210th Zhenyu-Bo 294 228 11ms 30 Jul 2025 211th EthanJantz 291 230 11ms 5 Sep 2025 212th RobertBurs 283 237 10ms 22 Sep 2025 213th TJK-S 278 241 11ms 25 Oct 2025 213th NoneTheFewer 278 241 11ms 25 Dec 2025 215th te-chnical 260 258 219ms 4 May 2025 216th arebbsba 226 296 11ms 9 Jan 2025 217th kasarino 224 299 11ms 8 Feb 2026 218th benanlam 209 320 10ms 21 Dec 2025 219th AidanWalter 124 540 10ms 1 Jan 2025 220th bignamehyp 100 667 10ms 14 Nov 2024 First Prev 161–220 of 220
