Showing posts with label extreme. Show all posts
Showing posts with label extreme. Show all posts
Tuesday, 4 March 2025
Sunday, 10 November 2024
Saturday, 15 June 2024
Thursday, 9 May 2024
Sunday, 3 December 2023
Wednesday, 18 October 2023
Monday, 12 June 2023
Friday, 21 April 2023
Thursday, 26 January 2023
Sudoku no 692 (Extreme)
This puzzle is very difficult. Please add a comment below if you manage to solve it.
Saturday, 17 December 2022
Sudoku no 686 (Extreme)
This puzzle has a Hodoku grade of 18788.
Andrew Stuart's solver was unable to grade it.
Sunday, 4 December 2022
Monday, 3 October 2022
Thursday, 14 July 2022
Thursday, 16 June 2022
Friday, 27 May 2022
Sudoku no 658 (Extreme)
This puzzle is at the lower end of the extreme category but I am still using it because, according to Andrew Stuart's grader and solver (see link below), the swordfish technique will help you to solve it. Our younger son created the puzzle using a Javascript program which he wrote himself:
Solve online
Saturday, 30 April 2022
121 Extreme Sudoku Puzzles
Some time ago, I ran my sudoku creation program 10,000 times with the idea of creating enough extreme puzzles to fill a book which I could sell on Amazon and elsewhere. I intended to format the puzzles in Andrew Stuart's grader and solver, copy them into a Google Doc and save it as a PDF, which I could then turn into a paperback.
I soon realised that this was going to take longer than expected and gave it up as a bad job. I am now working on a computer application which will create the book for me.
The puzzles I created are therefore surplus to requirements so I have pasted them below. Each one shows its Hodoku grade and you will notice that I have only included puzzles with a grade over 5000.
The puzzles were created before I amended my C program to avoid occasional pattern repetition as explained here. However, this should not be a problem as this is present in all the commercially available puzzles I have ever seen. I seem to be the only person bothered by it:
000003000095800006006540000120000030500300008000070040000000071004000600380000009 #1 Extreme (5102)
200054086005060000000000030070010600000006010000900042401000007000800490007009000 #1 Extreme (5574)
000807000702005001090000400009000300070900006000200590807050000400030000000080250 #1 Extreme (5518)
030104000065020004200007500040600000500000006000008049670000010000200703902000000 #1 Extreme (5054)
800090000300502000000000007600000030000001072520030960003010009005400000000280010 #1 Extreme (5018)
000904006030000084060800300050070000910008000006105008000059230000000009700200060 #1 Extreme (5946)
003900100000060407400002000000034600020100050000000080602301908000000700010000003 #1 Extreme (5338)
000003000239000000700806090000308620000260070000005409008000000400070800097000040 #1 Extreme (5620)
010020000408000003050700008000000015030000000800019040000002000005000006600094070 #1 Extreme (5436)
800740020007000000040005030904000061073000080080600700009206000000100500460000000 #1 Extreme (5000)
007060029000000000050290048700001000006050090080000000002080001000075380300900000 #1 Extreme (5574)
690000800000608070000040000000000001009301000700205000080000200030500700040980060 #1 Extreme (5592)
000000900700000041000821000007000000280100039000004008030500000004060390502090010 #1 Extreme (5504)
000900003972600100000005200700006000091040000800000010607208050005000072030500000 #1 Extreme (5470)
000130000005006004390007000023000700514700600000000002900080010000300060008000239 #1 Extreme (5990)
000904008070000000600310500400000070027800010106040002000030000000150400009006080 #1 Extreme (5034)
000040065800000100005701000300079014610003700004000000720008900000004000000010020 #1 Extreme (5204)
090102005054030000002049800200050000000807010010300600046000900580000140000000006 #1 Extreme (5218)
060000004820000700300806000002004000000200090050080100400000008603907000000100300 #1 Extreme (5448)
107200600080030000000104000509041002300009040002000007003400090000006020000500006 #1 Extreme (5584)
018000007072000063300000000030002040007030600100004700001800900400000500080070000 #1 Extreme (5204)
000070600000500700400060085004000300050300819830001000701000040006180000500002000 #1 Extreme (5710)
300080010010900700000240006540006000091002000200000040005800401009000270004300060 #1 Extreme (5626)
009020034054010020000600070016000000020460000500007000090000000000005010800390200 #1 Extreme (5988)
000080000009103040000000603060500700000097000000040008170900300800000090400070002 #1 Extreme (5542)
002006000100004000059100230000020500000000080320000000090080005010009300700300906 #1 Extreme (5198)
607800000020700003003000001900020080000960007400000900700000090204050100000001500 #1 Extreme (5814)
000000600000085010000012900107000009000000030009007082302000067500400000040009000 #1 Extreme (5692)
000800120080006000350070000070900004200008090030100702000000930023040000000080007 #1 Extreme (5734)
000100503100905000000280006290500600000007000300010002030800000006000020008000370 #1 Extreme (5108)
000082300030007000001000080008401006000000900006200010007800605000053702090000000 #1 Extreme (5138)
006000501047000000000000490400089120261004000000000040008700000910048070000902000 #1 Extreme (5130)
010050000030000607046008900001040000052071003000300000500010048000000000000002790 #1 Extreme (5158)
300020040000040093006000800900130560000000000500000007080000600402006010001800000 #1 Extreme (5490)
001090000000000002309201080040100000050340200100008007000002308005000000807400105 #1 Extreme (5080)
040050100000300020900006000020008090001207050300160000007004800059000407000000060 #1 Extreme (5274)
060000170030500400700009305000903000270010004001000700000400900840000060000000003 #1 Extreme (5368)
000300000302060007006002530700000094009000000050003600007041000400080306080000700 #1 Extreme (5870)
300200009800501700001000040020045000000900000047800003709000300000003000000000617 #1 Extreme (5950)
009000300000000090026003005000000000000009572100720030005000040060087000703602000 #1 Extreme (5408)
008060502100000008000000430504301009030500040970008000005800000400906380000200700 #1 Extreme (5294)
005302000070040000001007920000425007000039001000000050708000003034000060090050800 #1 Extreme (5930)
040000001003005098520000000008470000000000580000300006007000000200009700000100034 #1 Extreme (5136)
000302700038046000000010000076104000003000000000000904000000002800020090004580013 #1 Extreme (5118)
000005080000300006069040000900000450003060700080003090104830000000700000300000020 #1 Extreme (5502)
600730010003000760000002000009173000305900000007000400500010006200040900090020030 #1 Extreme (5280)
000000050048000600103050000900024536200080004000009070020900160000600700009075000 #1 Extreme (5316)
006000400802003100005700063050004030000080090200005000008010004600000000401200000 #1 Extreme (5388)
000000300019062000000900010020000800405120600000000070000000004082037050003001000 #1 Extreme (5012)
000038000000050000000000709078009000620004000040080050760000004000016200002300100 #1 Extreme (5538)
010520000020006007600000201003200000004000000500130090900000030000078600000000084 #1 Extreme (5132)
005104090070000500004080006420600000003000001000900028000090050600350002030700000 #1 Extreme (6920)
700080000030670804001050020000000200906000040000800593000040000040003001600100080 #1 Extreme (6270)
000030080008000700000400096037002600005007048060100000000900000040210000000000137 #1 Extreme (6074)
830040000007080109001700300012000000008600004600000050000107400000004203003000010 #1 Extreme (6996)
000030000007005008800090200000607000045000002000200300000001730009000000004300060 #1 Extreme (6970)
004000000070002006010007900050000201000503000090000000003008040100090008008040503 #1 Extreme (6152)
000800400070034020006507008300019000020000080007000004060005003089000060010000500 #1 Extreme (6394)
006090080900000300010007020009100000570903000068020000000400800005000042100030056 #1 Extreme (6626)
000100907504020800008000004200000040000000300000570090000030000402600530100409060 #1 Extreme (6036)
005601900600004000000050200206000030030020010109403000000000620300500004000009007 #1 Extreme (6434)
200007000009000004100300080060000002007400638000009100006008000501000000003605420 #1 Extreme (6696)
100900000008040000090200001080000009000700500200030860001000020004076000003010480 #1 Extreme (6028)
700006902002007000900300760509700001040000090300000200000400008005090000604102000 #1 Extreme (6120)
008040030904200000000070000760009100000016020500300400005000000010090700800000092 #1 Extreme (6028)
960100000500304000300809001000000082003000000100905700200048039004500107000000000 #1 Extreme (6616)
030006002050800000609004000472000000000000063000090200005030900000008300180000640 #1 Extreme (6878)
070000000060200900009780100200070804014000000008600030040030000050000067000100000 #1 Extreme (6482)
300007005000639000060005904020003070000000000801020006400070500600800010000000008 #1 Extreme (6782)
096700010070000005800400700002004000701000000000601087000090030300140800060803000 #1 Extreme (6100)
029003000408000069000000800002700000800005000105062094000006050706020900200300680 #1 Extreme (6192)
000000402008107009092008000400000000007800004050600030100003028000009700030000100 #1 Extreme (6104)
000490006000010000040002075010600500034000008060040030370020061000800000200070300 #1 Extreme (6056)
000300701090002004000060000008053010010000900600000308140500027900000000502004009 #1 Extreme (6390)
010000000205080000300004126000300002800007400060900000001000500009010048400000009 #1 Extreme (6550)
006040000500600180030002050000230005700000008000109200000065830000000000605000091 #1 Extreme (6024)
000058092900000700040070030060007000070020500002100004306000000091003080000902000 #1 Extreme (6610)
000000020040000730010030406005000803037006000900040000090204000000380050803000001 #1 Extreme (6320)
071000002009170040050006000000002000010400900005000083080047005900520004000601700 #1 Extreme (6282)
600005000000000080201800007004000900500200608000009004010508000062091000003002400 #1 Extreme (6274)
410000009060100002009067000095000000000009070103080500300000000080500210000070400 #1 Extreme (6224)
052400093009000800310007000007085000500100000000270008090540000030000025670000040 #1 Extreme (6238)
080004020000000040300060009000000200005020003040009000006030000070600090010002800 #1 Extreme (6290)
500060090003040006080002000007000004100030000000906010000810230020000058050000007 #1 Extreme (6448)
000080000470020806300100020060000090205000400007900001040000008500006002000010630 #1 Extreme (6324)
001460000080200600200000050048030060503000100000000005002000010030071008070500000 #1 Extreme (6528)
000401500064005000003082000600510070000000090080000006050020609409008000200000100 #1 Extreme (6364)
000680705500000420000000000600010308004002000091000070008009000900350000070040001 #1 Extreme (7078)
050410006100670000000009000200800400005040730000500001408000000001794800370000600 #1 Extreme (7372)
000000062005009010000000903006350000004070051030200008070000495300000000000010000 #1 Extreme (7692)
203000500090000027005040000010092008000000060400805000080706000002300000900000200 #1 Extreme (7348)
100005000000001400003040012000000086000070930060000000340028050600590000800000700 #1 Extreme (7238)
400010070065000000100000008029070000000058000007020040700001060040006003080000102 #1 Extreme (7714)
000900027100002000080000001050060208060083040700000060009140000000008500006000070 #1 Extreme (7396)
400070006007650034050000000028700000060000803000009000000100080240030010806400000 #1 Extreme (7024)
029000000400690000006008200010039050000100094000000810001900030780000000000005060 #1 Extreme (7388)
000000710003700060840003900008009005300000084000060000500006000010200040002900000 #1 Extreme (7342)
009000000400230000083500071000000000030000407000070205940006020000802000060000150 #1 Extreme (7504)
090000076008000009002000000000040805470000090000600010610500300800720000040001000 #1 Extreme (7344)
004005008001079000600010700900000006000032000083900100000050602400100079007000080 #1 Extreme (7172)
000103700007009050060000089050600000900051204002000005003000921090004000700000000 #1 Extreme (7324)
030400090000000053140060008007200000900040060010009000061000005005103200000000900 #1 Extreme (7740)
500100000090003000200097400600008031000200000080010020730005900010000008008000000 #1 Extreme (7578)
050070030609020500004008000200080700003001005008000060300060000000000617400200800 #1 Extreme (7624)
034000000160040000800200300000036008000500000090017000000005000040900680500000072 #1 Extreme (7042)
000004010050170000000800002000000380800635000600400700001000030090301804080090000 #1 Extreme (7008)
010408000000700150000000070000130006800020000200005037040000001093000060620000800 #1 Extreme (7720)
000035000071900000000002300000100400080000000009080500005000140130000680408000903 #1 Extreme (7514)
030600000401002006080740000062000007900010000800527000000000650300000109004060002 #1 Extreme (7150)
000000760005800002200000900008074000309050080040030000050600000700090010030000400 #1 Extreme (7928)
410700005005960800000000020040091003800050009007000000080000060123500900000020000 #1 Extreme (8610)
030010900081002600200500300106400000000000030000690470017000000009000060000100800 #1 Extreme (8594)
005020030700000000100680020004390002800000006001000400000050090000009800008064007 #1 Extreme (8288)
000046000571090000000000039050800070080060000300007000000002703124000050000050400 #1 Extreme (8420)
090007604000000000700000390004300000009005070050800030200000050008006001600400000 #1 Extreme (8304)
000008900003004600070600034300020009500400060000703000609300007100000000080009040 #1 Extreme (9722)
000010007930020000000000650857460020000000700020801000400500003200000080060000470 #1 Extreme (9840)
000000003200001500017020004400093001050000000600050300008275000000000000020040600 #1 Extreme (9188)
940000000001000002008504300600200090000006001000000700090300005106070800470000000 #1 Extreme (12668)
000010020000007000008500907030060500001000060400005802000000096750300000020004700 #1 Extreme (13280)
000000400620000000003007910005091000970020000000800030700009006000005090000180004 #1 Extreme (18516)
Monday, 25 April 2022
One of The Hardest Sudokus from The New Sudoku Players' Forum
I revisited The New Sudoku Players' Forum for the first time in a while and found a thread called the hardest sudokus. It has a link which allows you to download a copy of their hardest sudokus database. You can try the first puzzle from this database below. I'm not in the habit of copying other people's work so if you want any more you will have to get them yourself:
Solve online
Thursday, 31 March 2022
Sunday, 6 March 2022
Friday, 25 February 2022
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