[math-fun] World's hardest sudoku puzzle?
Agence France-Presse news (Escargot = Snail in French). A FINNISH mathematician claimed he had created the world's hardest sudoku puzzle, a brain-teaser which required three months' work and a billion combinations to produce. "AI Escargot is the most difficult sudoku-puzzle known so far," the puzzle's 37-year-old creator and applied mathematician Arto Inkala said. "I called the puzzle AI Escargot, because it looks like a snail. Solving it is like an intellectual culinary pleasure. AI are my initials," Mr Inkala said. According to a rating published on sudoku website www.sudoku.com, AI Escargot claims the top spot for sudoku's most baffling puzzles. Escargot demands those tackling it to consider eight casual relationships simultaneously, while the most complicated variants attempted by the general public require people to think of only one or two combinations at any one time. AI Escargot has, however, been solved by sudoku experts, but its creator has promised to produce more challenging versions, as with Escargot, with the aid of computers. +-------+-------+-------+ | 1 . . | . . 7 | . 9 . | | . 3 . | . 2 . | . . 8 | | . . 9 | 6 . . | 5 . . | +-------+-------+-------+ | . . 5 | 3 . . | 9 . . | | . 1 . | . 8 . | . . 2 | | 6 . . | . . 4 | . . . | +-------+-------+-------+ | 3 . . | . . . | . 1 . | | . 4 . | . . . | . . 7 | | . . 7 | . . . | 3 . . | +-------+-------+-------+ References: Text above is a copy and paste from: http://www.news.com.au/story/0,23599,20714995-38200,00.html The puzzle was unfortunately not in the news, but I found the grid here: http://www.sudoku.com/forums/viewtopic.php?t=4870 Christian.
got a solution in 30 min. using my Mma-solver and manual backtrack; any others? W. ps. if you write all digits of row1..5 concatenated, and factor it, then the biggest prime factor of it is 5005037036778279015446739746032691 while the rows 6..9 give 12534318159776218231; and that shouldn't spoil your fun. ----- Original Message ----- From: "Christian Boyer" <cboyer@club-internet.fr> To: "'math-fun'" <math-fun@mailman.xmission.com> Sent: Tuesday, November 07, 2006 10:42 AM Subject: [math-fun] World's hardest sudoku puzzle?
Agence France-Presse news (Escargot = Snail in French).
A FINNISH mathematician claimed he had created the world's hardest sudoku puzzle, a brain-teaser which required three months' work and a billion combinations to produce.
"AI Escargot is the most difficult sudoku-puzzle known so far," the puzzle's 37-year-old creator and applied mathematician Arto Inkala said.
"I called the puzzle AI Escargot, because it looks like a snail. Solving it is like an intellectual culinary pleasure. AI are my initials," Mr Inkala said.
According to a rating published on sudoku website www.sudoku.com, AI Escargot claims the top spot for sudoku's most baffling puzzles.
Escargot demands those tackling it to consider eight casual relationships simultaneously, while the most complicated variants attempted by the general public require people to think of only one or two combinations at any one time.
AI Escargot has, however, been solved by sudoku experts, but its creator has promised to produce more challenging versions, as with Escargot, with the aid of computers.
+-------+-------+-------+ | 1 . . | . . 7 | . 9 . | | . 3 . | . 2 . | . . 8 | | . . 9 | 6 . . | 5 . . | +-------+-------+-------+ | . . 5 | 3 . . | 9 . . | | . 1 . | . 8 . | . . 2 | | 6 . . | . . 4 | . . . | +-------+-------+-------+ | 3 . . | . . . | . 1 . | | . 4 . | . . . | . . 7 | | . . 7 | . . . | 3 . . | +-------+-------+-------+
References: Text above is a copy and paste from: http://www.news.com.au/story/0,23599,20714995-38200,00.html
The puzzle was unfortunately not in the news, but I found the grid here: http://www.sudoku.com/forums/viewtopic.php?t=4870
Christian.
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Takes ~30sec on my laptop, using the R library for sudoku:
library("sudoku") solveSudoku(readSudoku("worlds-most-difficult-sudoku.txt")) [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [1,] 1 6 2 8 5 7 4 9 3 [2,] 5 3 4 1 2 9 6 7 8 [3,] 7 8 9 6 4 3 5 2 1 [4,] 4 7 5 3 1 2 9 8 6 [5,] 9 1 3 5 8 6 7 4 2 [6,] 6 2 8 7 9 4 1 3 5 [7,] 3 5 6 4 7 8 2 1 9 [8,] 2 4 1 9 3 5 8 6 7 [9,] 8 9 7 2 6 1 3 5 4
Of course, using a computer might properly be regarded as cheating... :-)
Date: Tue, 7 Nov 2006 23:01:34 +0100 From: "wouter meeussen" <wouter.meeussen@pandora.be>
got a solution in 30 min. using my Mma-solver and manual backtrack; any others?
From: "Christian Boyer" <cboyer@club-internet.fr> To: "'math-fun'" <math-fun@mailman.xmission.com>
+-------+-------+-------+ | 1 . . | . . 7 | . 9 . | | . 3 . | . 2 . | . . 8 | | . . 9 | 6 . . | 5 . . | +-------+-------+-------+ | . . 5 | 3 . . | 9 . . | | . 1 . | . 8 . | . . 2 | | 6 . . | . . 4 | . . . | +-------+-------+-------+ | 3 . . | . . . | . 1 . | | . 4 . | . . . | . . 7 | | . . 7 | . . . | 3 . . | +-------+-------+-------+ -- Steve Rowley <sgr@alum.mit.edu> http://alum.mit.edu/www/sgr/ Skype: sgr000
participants (3)
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Christian Boyer -
Steve Rowley -
wouter meeussen