The Gray Code Decoder and Gray Code Encoder holes will go live in approximately 27 hours. Why not try and solve them ahead of time?
Card Number Validation in Python 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 159th kistlerf 🇨🇭 580 143 17ms 19 May 2025 162nd hiichbindermax 576 144 17ms 2 Oct 2024 162nd mathisfun271 576 144 10ms 14 Oct 2024 162nd bob-th 576 144 10ms 22 Oct 2024 165th JunkIce 572 145 10ms 3 Dec 2024 166th croc54 568 146 10ms 15 Dec 2024 167th PyryL 🇫🇮 565 147 10ms 1 Mar 2025 168th mbittner20 561 148 10ms 13 Oct 2024 168th YAJUE114514 561 148 10ms 12 Dec 2025 170th psaban 557 149 15ms 31 Jul 2025 170th TheZwierzLF 🇵🇱 557 149 11ms 24 Nov 2025 170th RodAlc24 🇪🇸 557 149 17ms 22 Feb 2026 173rd FlorianCassayre 🇫🇷 553 150 18ms 1 Oct 2024 173rd jameswmccarty 553 150 10ms 5 Oct 2024 173rd yousefalizadeh 553 150 10ms 23 Oct 2024 173rd feherd 553 150 11ms 31 Oct 2024 173rd kadamkaustubh 553 150 10ms 8 Nov 2025 178th adamnielson42 🇺🇸 546 152 10ms 6 Oct 2024 178th voidgloom 546 152 10ms 22 Oct 2024 178th omero-san 546 152 10ms 22 Sep 2025 178th brochmann 🇸🇪 546 152 10ms 12 Oct 2025 182nd xyangst 542 153 11ms 1 Oct 2024 182nd denisfouchard 542 153 10ms 21 Aug 2025 184th osNiko 🇧🇷 539 154 9ms 21 Aug 2025 185th robin-scragg 535 155 11ms 21 Aug 2025 185th celiendonze 🇨🇭 535 155 10ms 17 Oct 2025 185th aksyristos 535 155 10ms 21 days ago 188th travisdoesmath 532 156 10ms 7 Sep 2025 188th Shotokhan 532 156 10ms 21 Sep 2025 190th lhulinsky 529 157 10ms 21 Oct 2024 191st ellis-rix 525 158 10ms 9 Dec 2024 192nd webmiche 522 159 11ms 3 Nov 2025 193rd CheeseCake628 🇳🇴 519 160 104ms 5 Nov 2024 194th pres-abhisheksinha 516 161 10ms 8 Oct 2024 195th ibixina 512 162 11ms 13 Oct 2024 195th TheAtrossian 512 162 11ms 5 Jan 2025 197th Vaekor 503 165 11ms 15 Dec 2024 198th JesseNoEyes 🇺🇸 491 169 11ms 1 Oct 2024 199th zyc-2024 🇨🇳 488 170 10ms 5 Oct 2024 200th ComputerKWasTaken 🇺🇸 485 171 10ms 14 Oct 2024 201st navier-1 480 173 10ms 22 Sep 2025 202nd clayboll99 472 176 10ms 10 Jul 2025 203rd muser-logiccpu 🇺🇦 469 177 18ms 9 Aug 2025 204th OSYCh314 🇦🇺 466 178 10ms 2 Nov 2024 205th calum12345 461 180 10ms 26 Mar 2025 206th zt14427 456 182 11ms 27 Dec 2024 207th IoLimmer 454 183 10ms 10 Oct 2024 208th estomagordo 🇳🇱 446 186 10ms 15 Jul 2025 209th gautambp 381 218 11ms 24 Jun 2025 210th Zhenyu-Bo 364 228 11ms 30 Jul 2025 211th EthanJantz 361 230 11ms 5 Sep 2025 212th RobertBurs 350 237 10ms 22 Sep 2025 213th TJK-S 344 241 11ms 25 Oct 2025 213th NoneTheFewer 344 241 11ms 25 Dec 2025 215th te-chnical 322 258 219ms 4 May 2025 216th ComradeSquirrel 314 264 10ms 18 hours ago 217th arebbsba 280 296 11ms 9 Jan 2025 218th kasarino 278 299 11ms 8 Feb 2026 219th benanlam 259 320 10ms 21 Dec 2025 220th AidanWalter 154 540 10ms 1 Jan 2025 221st bignamehyp 124 667 10ms 14 Nov 2024 First Prev 161–221 of 221
