Thankyou
MoschopulusI fully appreciate what checker was originally intended to do - and how well it has been improved.
If we wanted to we could easily modify it to count up the number of puzzles in the mc grid [at least in the 21,22,23 clue levels].
Effectivly by introducing furthur constraints we can increase the mcn to 18 - as has been mentioned - this will occur in bands [1,30,310,413] according to the index416 program. [as described previously][may not even be necessary]
We can fix equivalent clues I think according to this pattern which reduces the total number of grids by up to 648. .......its took me a while........and I wracked my brain.......but the answer was there all along [in this post !]
The essential clues are a partial 7/9 Rook pattern [ 2 classes only ] [there is no 8/9 in the 20 puzzle]
Every puzzle in the MC grid [apart from puzzles with 3 empty boxes - and they have a minimum of 23 clues] has this 7/9 rook pattern somewhere in it - it is difficult ?impossible to avoid it.
I had initially thought that all the 7/9 rook patterns were the same ....but it appears not.
Here is a 20 clue puzzle from the mc grid
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+---+---+---+
|12.|...|...|
|..6|...|..3|
|...|..3|45.|
+---+---+---+
|..1|.6.|8..|
|5..|..7|2..|
|.9.|...|...|
+---+---+---+
|...|..5|.7.|
|...|9..|...|
|..8|.1.|6..|
+---+---+---+
and one of the 7/9 rook patterns
+---+---+---+
|1..|...|...|
|...|...|..3|
|...|...|...|
+---+---+---+
|...|.6.|...|
|...|...|2..|
|.9.|...|...|
+---+---+---+
|...|...|.7.|
|...|...|...|
|..8|...|...|
+---+---+---+
Checker only allows me to insert clues according to precalculated sets..
Running checker with fixed clues as allowed - positions 11 and 45 and we will see what the output for fixing 2 clues is. I will then manually seive the 7/9 rookery pattern above...........................................
- Code: Select all
Finished. Total computation time was 0d 02h 06m.
Only a partial search was done -- searched the branch whose first clues are 11, 45
There are 11 20-puzzles in this branch (all puzzles were solved).
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100000080050009100700000006000060000004800030000001500002005970040000000008300000
103000080000709000080020000200060007004000030000000500000005000600070002900300040
100000009006700020080000000000064000500000031000200500002600070000008000900010040
100000009006080100700000050030060807004000000090200000000005000040900002000010600
120000009000780000009003000000060000500007030800200004300005070040000002000000600
100000000050000003009020400030060807004090000000200000000005900000008010070300005
100000000006080000009003450001060800000007030000200000300005070040000002070000600
100000000006000020080003400000060800000090001007200060002005970040008000000300000
120000000006000003000003450001060800500007200090000000000005070000900000008010600 X
100000000050009000080020406200060007004000030007000500010005900000070002000300000
103000000050000020000020406000060007000800000090001500010005900600070300008000000
Using the five 7/9 rookerys from the above grid that I can find - this is essentially the same for all the isomorphic 20 puzzles
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1................3.............6..........2...9..............7............8......
1......................3.......6..........2..................7....9.......8......
1................3.............6..........2...9............5..............8......
.2.....................3.......6....5........................7....9.......8......
.2......................4......6....5........................7....9.......8......
- Code: Select all
1................3.............6..........2...9..............7............8...... 1 solution
1......................3.......6..........2..................7....9.......8...... 1 solution
1................3.............6..........2...9............5..............8...... 1 solution
.2.....................3.......6....5........................7....9.......8...... 1 solution
120000000006000003000003450001060800500007200090000000000005070000900000008010600
.2......................4......6....5........................7....9.......8...... 2 solutions
020000009006780003000000400001060000500000000090200004000005070000900010008010600
.x.........x.....x......x....x.x....x.........x............x.x....x.......x.x.x..
So four out of the five rookery patterns define the isomorph puzzle there
One of the five has two solutions.......the two isomorphs have 14 clues in common......how strange.
But not all 7/9 rookery patterns define a puzzle. That would figure...There must be more than I realize.....
Red Ed wrote:The MC grid has [9/9] Rookery Templates =2241
Indeed there are.
C