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| rubylips
| Joined: 07 Apr 2005 | Posts: 62 | : | Location: London | Items |
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Posted: Tue Apr 26, 2005 11:27 am Post subject: Swordfish compendium |
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I know that I've thrown up a few red herrings over the past couple of weeks but I now think I've firmly got to grips with the swordfish - thanks to plenty of help from simes and IJ. Here's a compendium of puzzles, each of which is able to be solved logically (no Nishio) provided that the swordfish is found. Some of the puzzles are new while others have been lifted from existing topics.
Puzzle 1:
Code: | . 8 . | . . . | 6 1 .
1 . . | . 9 . | 2 . .
2 . . | . . 5 | . . 4
----------------------
9 . . | . . . | . 7 .
. . . | 3 2 6 | . . .
. 4 . | . . . | . . 1
----------------------
6 . . | 8 . . | . . 3
. . 3 | . 1 . | . . 5
. 1 7 | . . . | . 9 . |
Puzzle 2:
Code: | . . 2 | . . 5 | 3 7 .
7 . . | 9 . . | . . 8
6 1 . | . . . | . . .
----------------------
. . 8 | . 1 . | . . .
. 7 . | . 3 . | . 5 .
. . . | . 2 . | 4 . .
----------------------
. . . | . . . | . 3 2
5 . . | . . 6 | . . 7
. 4 1 | 7 . . | 9 . . |
Puzzle 3:
Code: | . . . | 4 7 . | 6 . .
. . 4 | . . . | 3 . 5
9 2 . | . . . | . . .
----------------------
. 3 1 | . . . | . . .
. . . | 9 3 6 | . . .
. . . | . . . | 2 8 .
----------------------
. . . | . . . | . 1 6
4 . 8 | . . . | 9 . .
. . 7 | . 5 2 | . . . |
Puzzle 4:
Code: | . 1 . | . . . | 8 . 3
5 . . | . 9 6 | . . .
. . 4 | . . . | . 6 .
----------------------
9 . . | 4 . 3 | . . .
. 2 . | . . . | . 1 .
. . . | 8 . 5 | . . 7
----------------------
. 6 . | . . . | 4 . .
. . . | 1 7 . | . . 5
1 . 3 | . . . | . 2 . |
Puzzle 5:
Code: | . 4 . | . . . | . . 9
8 . . | 7 . . | . 5 .
. . 1 | . . 8 | 2 . .
----------------------
. . . | . 9 . | . . 8
2 . . | . 4 . | . . 6
5 . . | . 6 . | . . .
----------------------
. . 8 | 2 . . | 7 . .
. 6 . | . . 1 | . . 4
9 . . | . . . | . 3 . |
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| rubylips
| Joined: 07 Apr 2005 | Posts: 62 | : | Location: London | Items |
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Posted: Tue Apr 26, 2005 9:14 pm Post subject: |
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Puzzle 6:
Code: | 8 . . | . . . | . 5 9
. 6 . | . 2 . | . . 4
5 . . | . . 1 | 7 . .
----------------------
. 5 . | . . . | 3 . .
. . . | 4 9 7 | . . .
. . 2 | . . . | . 6 .
----------------------
. . 8 | 5 . . | . . 3
7 . . | . 6 . | . 8 .
4 3 . | . . . | . . 1 |
Puzzle 7:
Code: | 5 . . | . . . | . . 4
. 8 9 | . . 3 | . 7 .
. 6 7 | 2 . . | . . .
----------------------
. . 3 | . 7 . | . . .
. 2 . | . 6 . | . 9 .
. . . | . 1 . | 8 . .
----------------------
. . . | . . 9 | 4 3 .
. 4 . | 8 . . | 6 5 .
8 . . | . . . | . . 1 |
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| Animator
| Joined: 26 Apr 2005 | Posts: 18 | : | | Items |
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Posted: Wed Apr 27, 2005 1:53 pm Post subject: |
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Are you sure puzzle 5 and 7 are correct? |
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| Tempbow
| Joined: 18 Apr 2005 | Posts: 22 | : | | Items |
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Posted: Sat Apr 30, 2005 2:07 am Post subject: |
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Animator wrote: | Are you sure puzzle 5 and 7 are correct? |
I found them OK, and containing swordfish examples:
Number 5 Code: | +---+---+---+
| 4 |6 | 9|
|8 |7 4|65 |
|6 1|9 8|24 |
+---+---+---+
|1 6| 9 |4 8|
|2 | 4 |5 6|
|5 4| 6 | |
+---+---+---+
|4 8|2 9|76 |
| 6 | 1| 4|
|9 |4 6| 3 |
+---+---+---+
POSSIBLE ENTRIES:
37 4 2357 6 12 35 138 178 9
8 239 239 7 12 4 6 5 13
6 357 1 9 35 8 2 4 37
1 37 6 35 9 2357 4 27 8
2 3789 379 18 4 37 5 179 6
5 789 4 18 6 27 139 1279 1237
4 135 8 2 35 9 7 6 15
37 6 2357 35 78 1 89 289 4
9 1257 257 4 78 6 18 3 125
=====
Target is 81, solved: 39 poss count: 150
+---+---+---+
|..5|..5|...|
|...|...|.*.|
|.5.|.5.|...|
+---+---+---+
|...|5.5|...|
|...|...|*..|
|*..|...|...|
+---+---+---+
|.5.|.5.|..5|
|..5|5..|...|
|.5.|...|..5|
+---+---+---+
Swordfish:
ROWS: found row 1 cols 3,6 row 4 cols 4,6 row 8 cols 3,4 for poss 5
POSSIBLE ENTRIES:
37 4 2357 6 12 35 138 178 9
8 239 239 7 12 4 6 5 13
6 357 1 9 35 8 2 4 37
1 37 6 35 9 2357 4 27 8
2 3789 379 18 4 37 5 179 6
5 789 4 18 6 27 139 1279 1237
4 135 8 2 35 9 7 6 15
37 6 2357 35 78 1 89 289 4
9 1257 27 4 78 6 18 3 125
=====
Target is 81, solved: 39 poss count: 149 Reduced by: 1
+---+---+---+
|745|623|819|
|829|714|653|
|631|958|247|
+---+---+---+
|176|395|428|
|283|147|596|
|594|862|371|
+---+---+---+
|418|239|765|
|362|571|984|
|957|486|132|
+---+---+---+ |
Number 7
Code: | +---+---+---+
|5 | | 4|
| 89| 3| 76|
| 67|2 | |
+---+---+---+
|6 3| 78| 42|
| 28| 6 | 9 |
| 4| 12|86 |
+---+---+---+
| | 9|438|
| 4 |8 |65 |
|8 | | 21|
+---+---+---+
POSSIBLE ENTRIES:
5 13 12 67 89 67 239 18 4
124 8 9 145 45 3 25 7 6
134 6 7 2 89 145 359 18 359
6 159 3 59 7 8 15 4 2
17 2 8 345 6 45 1357 9 357
79 579 4 359 1 2 8 6 357
127 17 56 156 25 9 4 3 8
39 4 12 8 23 17 6 5 79
8 39 56 4567 345 4567 79 2 1
Target is 81, solved: 36 poss count: 148
Swordfish:
COLUMNS: found col 3 rows 1,8 col 6 rows 3,8 col 8 rows 1,3 for poss 1
+---+---+---+
|.11|...|.1.|
|1..|1..|...|
|1..|..1|.1.|
+---+---+---+
|.1.|...|1..|
|1..|...|1..|
|...|.*.|...|
+---+---+---+
|11.|1..|...|
|..1|..1|...|
|...|...|..*|
+---+---+---+
POSSIBLE ENTRIES:
5 3 12 67 89 67 239 18 4
124 8 9 145 45 3 25 7 6
34 6 7 2 89 145 359 18 359
6 159 3 59 7 8 15 4 2
17 2 8 345 6 45 1357 9 357
79 579 4 359 1 2 8 6 357
127 17 56 156 25 9 4 3 8
39 4 12 8 23 17 6 5 79
8 39 56 4567 345 4567 79 2 1
=====
Target is 81, solved: 36 poss count: 146 Reduced by: 2
+---+---+---+
|532|786|914|
|189|543|276|
|467|291|385|
+---+---+---+
|613|978|542|
|728|465|193|
|954|312|867|
+---+---+---+
|276|159|438|
|341|827|659|
|895|634|721|
+---+---+---+ |
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| IJ
| Joined: 15 Apr 2005 | Posts: 16 | : | | Items |
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Posted: Sun May 01, 2005 12:35 am Post subject: |
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Is Puzzle 4 OK? I can solve all the others, but No 4 just ends up in a mess. I'm guessing I have a bug somewhere, but would appreciate another view... |
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| Animator
| Joined: 26 Apr 2005 | Posts: 18 | : | | Items |
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Posted: Sun May 01, 2005 11:20 am Post subject: |
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I solved them all except puzzle 5 (that is to say, without hints from here)
If you need a hint, then feel free to PM me... I prefer not to post it here since it may spoil the fun for some other people... |
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| IJ
| Joined: 15 Apr 2005 | Posts: 16 | : | | Items |
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Posted: Sun May 01, 2005 8:33 pm Post subject: |
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Thanks - I found the bug.
My code now solves puzzle 5 - based on the notes I made on your other post. |
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| AMcK
| Joined: 07 Apr 2005 | Posts: 89 | : | Location: Cambridge | Items |
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Posted: Fri May 20, 2005 10:57 am Post subject: Great puzzles! |
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Thanks to Rubylips for excellent 7 puzzles.
All solvable using colouring.
Puzzle 5 hardest because of conjugates in digts 3 and 5 and failure of colouring to reduce to single digit leaving N=3 work to complete.
Code: |
Puzzle 1:
Colouring for digit: 6
- - - - - - * - -
- - a b - - - - -
- b * - a - - - -
- a - - - - - - b
- - - - - * - - -
- - b - - - - a -
* - - - - - - - -
- - - a - - - b -
- - - * b - - - a
Row 3 reduction: digit 6 colours b/a cell {3,3} before 69 after 9
Row 9 reduction: digit 6 colours b/a cell {9,4} before 2456 after 245
Puzzle 2:
Colouring for digit: 2
- - * - - - - - -
- - - - - a b - -
- - - b - - * a -
* a - - - - - b -
b - - - - - a - -
- - - - * - - - -
- - - - - - - - *
- b - a - - - - -
a - - - - b - - -
Row 3 reduction: digit 2 colours b/a cell {3,7} before 25 after 5
Row 4 reduction: digit 2 colours a/b cell {4,1} before 2349 after 349
Puzzle 3:
Colouring for digit: 1
- a - - - - - - b
e * - - - f - - -
- - - - e - d - *
- - * - - - - - -
- - - - - - c - d
- - - f * e - - -
- - - - - - - * -
- e - - f - - - -
f - - e - - - - -
Row 2 reduction: digit 1 colours e/f cell {2,2} before 178 after 78
Row 6 reduction: digit 1 colours f/e cell {6,5} before 14 after 4
Puzzle 4:
Colouring for digit: 5
- - - * b - - a -
* - - - - - - - -
- - - a - - b - -
- a * - - - * b -
- - c - - - d - -
- - - - - * - - -
- - a b - - - - -
- - - - - - - - *
- b - - a - - - -
Row 1 reduction: digit 5 colours b/a cell {1,4} before 257 after 27
Row 4 reduction: digit 5 colours a/b cell {4,3} before 1578 after 178
Row 4 reduction: digit 5 colours a/b cell {4,7} before 25 after 2
Puzzle 5:
Colouring for digit: 3
c - * - - d b - -
- * * - - - - - *
- * - - c - - - *
- * - d - * - - -
- * * - - * - - -
- - - - - - a - b
- c - - d - - - -
d - * c - - - - -
- - - - - - - * -
Row 1 reduction: digit 3 colours c/d cell {1,3} before 2357 after 257
Row 1 reduction: digit 3 colours c/d cell {1,7} before 138 after 18
Row 8 reduction: digit 3 colours d/c cell {8,3} before 2357 after 257
Colouring for digit: 5
- - a - - b - - -
- - - - - - - * -
- b - - a - - - -
- - - b - a - - -
- - - - - - * - -
* - - - - - - - -
- * - - b - - - i
- - b a - - - - -
- * * - - - - - j
Column 3 reduction: digit 5 colours a/b cell {9,3} before 257 after 27
Puzzle 6:
Colouring for digit: 4
- a - - - b - - -
- - - - - - - - *
- - b - a - - - -
- - a - - - - b -
- - - * - - - - -
- b - - - - a - -
- - - - b * - a -
- - - - - a b - -
* - - - - - - - -
Row 7 reduction: digit 4 colours b/a cell {7,6} before 49 after 9
Puzzle 7:
Colouring for digit: 1
- * b - - - - a -
a - - b - - - - -
* - - - - a - b -
- c - - - - d - -
d - - - - - c - -
- - - - * - - - -
* * - a - - - - -
- - a - - b - - -
- - - - - - - - *
Row 1 reduction: digit 1 colours b/a cell {1,2} before 13 after 3
Row 3 reduction: digit 1 colours a/b cell {3,1} before 134 after 34
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Best regards
Andrew |
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| bking43
| Joined: 03 Jun 2005 | Posts: 1 | : | | Items |
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Posted: Fri Jun 03, 2005 5:04 pm Post subject: Ok, how about harder? |
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I took a quick peek at the first puzzle listed in this thread and solved it without much difficulty. I did need to figure out one new technique, which I presume is what people are calling "swordfish", though I haven't read the definition of that term.
I shall try the rest, but would like more of a challenge. So far I have worked a total of 5 sudoku puzzles, ranging from 2 easy, 1 medium, 1 hard and 1 swordfish.
Is there anything out there that is harder, but which can still be solved using logic alone (not requiring me writing a program to solve? I could, but have more fun doing these things with pen and paper.)
FWIW, I spent 8 years sucessfully pursuing degrees in mathematics (topology) many years ago, and have spent my adult life writing and designing computer programs and systems. I love logic.
Please feel free to reply to my email address or to here.
TIA, bking43@yahoo.com. _________________ bking43
.sig shows an old guy juggling 5 balls in a pattern every juggler knows is bogus. |
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| abailes
| Joined: 07 Jun 2005 | Posts: 2 | : | Location: London | Items |
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Posted: Tue Jun 07, 2005 8:22 pm Post subject: |
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bking,
Try your hand at this one:
http://www.sudoku.com/forums/viewtopic.php?t=387
And solve without trial and error.
I remain unconvinced there is not another nice sudoku theory lurking out there (although it will probably be impossible to spot in a puzzle if you find it).
Andrew |
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