The Calendar hole will go live in approximately 11 days. Why not try and solve it ahead of time?
All holes in C 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 Card Number Validation Catalan Numbers Catalan’s Constant Christmas Trees Collatz 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 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 Apéry’s Constant Binary Lambda Calculus Calendar Connect Four Continued Fractions Crossword CSS Colors (Inverse) CSS Grid Ellipse Perimeters Flags Floyd-Steinberg Dithering Gray Code Decoder Gray Code Encoder Hexagonal Spiral Highly Composite Numbers Multitap Input NFA Simulator Numbrix Odd Polyomino Tiling p-adic Expansion Polygon Triangulations QR Encoder Quadratic Formula Semiprime Numbers Smooth Numbers Snake Sphenic Numbers Taxicab Numbers Turtle Tutorial All Languages ><> 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 ALGOL 68 APL Arturo Befunge BQN CJam CoffeeScript Egel Fennel Harbour Hare Haxe Hush Hy iogii Knight Luau Odin Picat Qore Racket Rebol Rexx Scala Squirrel Stax Uiua Umka Vala Vyxal Bytes Chars Scoring Bytes Chars Language All ><> 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 ALGOL 68 APL Arturo Befunge BQN CJam CoffeeScript Egel Fennel Harbour Hare Haxe Hush Hy iogii Knight 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 Card Number Validation Catalan Numbers Catalan’s Constant Christmas Trees Collatz 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 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 Apéry’s Constant Binary Lambda Calculus Calendar Connect Four Continued Fractions Crossword CSS Colors (Inverse) CSS Grid Ellipse Perimeters Flags Floyd-Steinberg Dithering Gray Code Decoder Gray Code Encoder Hexagonal Spiral Highly Composite Numbers Multitap Input NFA Simulator Numbrix Odd Polyomino Tiling p-adic Expansion Polygon Triangulations QR Encoder Quadratic Formula Semiprime Numbers Smooth Numbers Snake Sphenic Numbers Taxicab Numbers Turtle Tutorial # Golfer Holes Points Bytes Submitted 881st Serentty 1 831 65 31 May 2020 882nd oonamo 2 830 1,638 29 Sep 2025 883rd Bodo171 2 822 284 6 Dec 2022 884th serenac26 1 821 56 2 May 2019 884th shuding 1 821 56 12 May 2020 884th desecaw13 1 821 56 24 Jan 2025 884th deglebe 1 821 56 3 Nov 2025 888th LuisGoncalves05 🇵🇹 1 821 525 17 Jul 2025 889th Rubiksmath 1 818 66 9 Oct 2023 890th ethanlchristensen 1 818 88 17 Oct 2025 891st MistyRevson 🇯🇵 1 818 527 29 Jul 2022 892nd Ocisaac 1 816 114 22 Mar 2024 893rd Planksu 1 811 74 10 Sep 2019 894th GReaperEx 1 809 89 11 Feb 2021 894th HVMarci 🇭🇺 1 809 89 3 Jun 2021 894th JosephPrachar 1 809 89 11 Jan 2023 897th francescolasco 2 809 702 19 Nov 2021 898th ieeemma 1 807 57 30 Apr 2020 898th Jigglypuffed 1 807 57 15 Jul 2025 900th foxmcloud555 2 807 1,155 28 Apr 2022 901st ibratcher 3 806 1,477 29 Oct 2023 902nd nagygeri97 1 803 76 1 Oct 2020 902nd mattiapenati 1 803 76 19 Dec 2020 902nd HHHMGK 1 803 76 2 Oct 2025 905th lifthrasiir 🇰🇷 1 803 147 30 Nov 2024 906th destofr 2 802 1,105 13 Oct 2022 907th kusune 🇯🇵 1 801 538 21 Sep 2023 908th pg98 1 800 75 17 Sep 2019 908th ryyyn 🇺🇸 1 800 75 28 Jan 2025 910th hyphz 1 800 90 14 Nov 2019 910th sulphemi 1 800 90 5 Oct 2023 912th pandaninjas 1 794 68 9 Aug 2023 913th bastienvoirin 🇫🇷 1 793 58 24 Apr 2020 913th bakaq 1 793 58 9 Nov 2021 913th Baxi-codes 1 793 58 25 Dec 2022 916th lgrandco 1 793 82 9 Oct 2024 917th resherra 2 793 441 26 Feb 2024 918th SB-945 5 793 4,234 15 Nov 2025 919th fourtf 1 791 91 28 Aug 2020 919th mazspork 1 791 91 4 Dec 2023 921st fergusleen 1 791 545 24 Dec 2023 922nd sleeppoo 2 790 307 18 Jul 2024 923rd SmileTheory 1 784 102 7 Jan 2021 924th winstonyli 1 784 550 27 Mar 2022 925th ishvanl 1 783 69 11 Jul 2022 925th cpchrispye 1 783 69 20 Apr 2024 927th maxgodfrey2004 🇨🇦 1 782 78 9 Jan 2025 928th cperry164 1 781 552 4 Jan 2022 929th matricronia 1 780 59 27 May 2021 929th kayahr 1 780 59 18 Jun 2021 929th aguyon1 1 780 59 17 Jun 2023 932nd adcpetechsoft 6 780 7,311 26 Mar 2025 933rd moririn2528 1 779 77 2 May 2019 934th Mr-McChicken 2 779 922 18 Oct 2023 935th mintyproof 1 778 63 29 Dec 2021 936th James-Oswald 🇺🇸 1 774 84 23 Aug 2024 937th KayzaFlo 1 774 137 3 Oct 2024 938th calum12345 2 773 355 27 Mar 2025 939th anlakii 1 772 79 16 Jul 2022 940th Ad1kCoder 2 770 325 14 Oct 2024 941st fastaire29 3 769 1,400 8 Oct 2022 942nd lesserfish 1 767 60 7 May 2021 942nd ClementCarre-BionomeeX 1 767 60 17 Nov 2021 942nd kasarino 1 767 60 21 days ago 945th JeromeSchweitzer 1 766 64 8 Sep 2020 946th scanlime 1 766 94 29 Dec 2020 946th qrakhen 1 766 94 13 Nov 2025 948th aviyanp 1 766 563 13 Oct 2025 949th azka1368 1 765 85 23 Nov 2023 950th C0de5mith 🇺🇸 1 764 72 22 Dec 2022 951st george1605 2 764 299 14 Feb 2023 952nd webmiche 1 763 80 31 Oct 2025 953rd janAkali 🇷🇺 1 759 79 5 Jul 2025 954th MoveCloudROY 1 758 95 18 Jan 2024 954th j2e2 🇪🇸 1 758 95 19 Feb 2025 954th ChausseBenjamin 🇨🇦 1 758 95 24 Apr 2025 957th esnethen 4 756 6,398 21 Feb 2023 958th inverseLorentz 🇦🇺 1 754 61 12 Oct 2023 959th petroselo 1 750 72 29 Aug 2021 960th gubug0 1 750 80 13 Mar 2019 First Prev 881–960 of 1,499 Next Last