[code]
5 8 9 l 3 2 4 l 1 6 7 l
6 3 7 l 1 8 5 l 4 9 2 l
1 2 4 l 7 9 6 l 5 8 3 l
_____________________
2 4 6 l 5 1 3 l 8 7 9 l
3 5 8 l 9 4 7 l 2 1 6 l
9 7 1 l 8 6 2 l 3 4 5 l
_____________________
4 1 3 l 6 5 9 l 7 2 8 l
8 9 5 l 2 7 1 l 6 3 4 l
7 6 2 l 4 6 8 l 9 5 1
in row 1 8-2-1-7 are givens r2 5-4-are givens, r3 no givens r4 1&9 R5 8, r6,5 r7, 4,3,9 r8 7,6 r9 6,8,5 As you can see I can solve, but not with the 1-9 on the diagonals, can someone help?
please give me some help for this x sudoku
8 posts
• Page 1 of 1
please give me some help for this x sudoku
by stevens » Mon Mar 20, 2006 4:16 pm
- stevens
- Posts: 9
- Joined: 15 March 2006
by CathyW » Mon Mar 20, 2006 6:11 pm
The starting grid for this puzzle is:
Computer solvers will say it has "too many solutions to count" unless they can take account of the diagonal requirement.
Nonetheless, it is a difficult puzzle and I'm stuck! Stevens you will find it easier to start again. Consider the diagonals like any other row or column to make eliminations i.e. neither 3 nor 7 can go in any cell on the top right to bottom left diagonal and 5 cannot go in any cell on the top left to bottom right.
Also when you get to a point with only two candidate entries for a particular number on the diagonals - you can use this to eliminate at the intersecting cell. For example in this puzzle, you get to a point where 8 must be in either r4c4 or r7c7 - thus you can eliminate 8 at r4c7 and r7c4 (unless these cells are already filled).
See how you get on. I'll post where I got to later.
BTW What's the prize?
- Code: Select all
*-----------*
|.8.|.2.|1.7|
|...|..5|4..|
|...|...|...|
|---+---+---|
|...|.1.|..9|
|..8|...|...|
|...|...|..5|
|---+---+---|
|4.3|..9|...|
|...|.7.|6..|
|.6.|..8|.5.|
*-----------*
Computer solvers will say it has "too many solutions to count" unless they can take account of the diagonal requirement.
Nonetheless, it is a difficult puzzle and I'm stuck! Stevens you will find it easier to start again. Consider the diagonals like any other row or column to make eliminations i.e. neither 3 nor 7 can go in any cell on the top right to bottom left diagonal and 5 cannot go in any cell on the top left to bottom right.
Also when you get to a point with only two candidate entries for a particular number on the diagonals - you can use this to eliminate at the intersecting cell. For example in this puzzle, you get to a point where 8 must be in either r4c4 or r7c7 - thus you can eliminate 8 at r4c7 and r7c4 (unless these cells are already filled).
See how you get on. I'll post where I got to later.
BTW What's the prize?
- CathyW
- Posts: 316
- Joined: 20 June 2005
by Ruud » Mon Mar 20, 2006 6:51 pm
The 5 in r4c4 may have been your first incorrect placement.
If you want to see the correct solution, select the text below this line:
5 8 4|3 2 6|1 9 7
7 1 6|9 8 5|4 2 3
2 3 9|7 4 1|5 8 6
-----+-----+-----
6 5 2|8 1 4|3 7 9
9 7 8|5 6 3|2 4 1
3 4 1|2 9 7|8 6 5
-----+-----+-----
4 2 3|6 5 9|7 1 8
8 9 5|1 7 2|6 3 4
1 6 7|4 3 8|9 5 2
Ruud.
If you want to see the correct solution, select the text below this line:
5 8 4|3 2 6|1 9 7
7 1 6|9 8 5|4 2 3
2 3 9|7 4 1|5 8 6
-----+-----+-----
6 5 2|8 1 4|3 7 9
9 7 8|5 6 3|2 4 1
3 4 1|2 9 7|8 6 5
-----+-----+-----
4 2 3|6 5 9|7 1 8
8 9 5|1 7 2|6 3 4
1 6 7|4 3 8|9 5 2
Ruud.
- Ruud
- Posts: 664
- Joined: 28 October 2005
by r.e.s. » Mon Mar 20, 2006 9:28 pm
Ruud,
Your two diagonals don't each have all the digits 1-9. Here's what I get as the unique solution (select to view) ...
586 324 197
712 985 463
349 167 528
654 712 389
978 543 216
231 896 745
423 659 871
895 271 634
167 438 952
Solving was nothing fancy -- there were many cases of the type CathyW mentioned, where a digit could be eliminated from an off-diagonal cell due to the digit having only two candidate-placements on a diagonal. There were also some "diagonal-box" interactions, where a digit was locked in one of the diagonal segments in the central box (box5).
Your two diagonals don't each have all the digits 1-9. Here's what I get as the unique solution (select to view) ...
586 324 197
712 985 463
349 167 528
654 712 389
978 543 216
231 896 745
423 659 871
895 271 634
167 438 952
Solving was nothing fancy -- there were many cases of the type CathyW mentioned, where a digit could be eliminated from an off-diagonal cell due to the digit having only two candidate-placements on a diagonal. There were also some "diagonal-box" interactions, where a digit was locked in one of the diagonal segments in the central box (box5).
- r.e.s.
- Posts: 337
- Joined: 31 August 2005
thank you all
by stevens » Tue Mar 21, 2006 12:05 am
for the help in solving these puzzles, I now have the right cords to go find the cache!!!!
- stevens
- Posts: 9
- Joined: 15 March 2006
8 posts
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