The New Sudoku Players' Forum

[m_b_metcalf]

Code: Select all

 . . 9 5 2 3 . . .
 . . 2 . . . 5 . .
 . . 3 . . . . 9 .
 . . 1 . . . 4 . .
 . . 5 3 8 6 . . .
 . . 8 . . . 3 . .
 . . 7 . . . . 3 .
 . . 6 . . . 1 . .
 . . 4 1 9 2 . . .   very hard

 . . 1 2 3 4 . . .
 . . 4 . . . 5 . .
 . . 6 . . . . 7 .
 . . 8 . . . 1 . .
 . . 2 9 1 8 . . .
 . . 3 . . . 9 . .
 . . 7 . . . . 8 .
 . . 5 . . . 7 . .
 . . 9 6 4 7 . . .   moderate

My SudokuX solver is only partially developed, but is enough to get through the hard puzzle.

You'll be able to get plenty of practice with this series!

Mike

[Leren]

The moderate puzzle was a one trick pony. The very hard puzzle was indeed very hard and required lots of forcing chains, which I checked using Andrew Stuart's Sudoku X solver.

So I added a full stop to the B pattern ie an extra clue in r9c9 to make the puzzle more interesting. Here is a cool X move in the solution - a double diagonal X Wing.

Code: Select all

*-----------------------------------------------------*
| 146    148   9 | 5    2     3    | 78  478   146    |
| 78     146   2 | 789  146   789  | 5   146   3      |
| 14578  14578 3 | 4678 146   1478 | 26  9     248    |
|----------------+-----------------+------------------|
| 267    3     1 | 29   57   *59   | 4   25678 568    |
| 2479   2479  5 | 3    8     6    | 79  127   19     |
| 2679   2679  8 | 24   1457 *145  | 3   267   569    |
|----------------+-----------------+------------------|
| 1289   1289  7 | 468  456   48-5 | 29  3     2489   |
| 289-5 *59    6 | 478  3     478  | 1  *45    2489-5 |
| 3      58    4 | 1    9     2    | 68  568   7      |
*-----------------------------------------------------*

X Wing on both Diagonals + Row 8 & Column 6 => - 5 r7c6, r8c19

Leren