More Homework 4

Everything about Sudoku that doesn't fit in one of the other sections

More Homework 4

What is the lowest number of clues of a valid and minimal puzzle included in this pattern?
Code: Select all
`+-------+-------+-------+| . . . | . . . | . . . || . x x | x x x | x x . || . x x | x x x | x x . |+-------+-------+-------+| . x x | . . . | x x . || . x x | . . . | x x . || . x x | . . . | x x . |+-------+-------+-------+| . x x | x x x | x x . || . x x | x x x | x x . || . . . | . . . | . . . |+-------+-------+-------+`

Here is an example:
Code: Select all
`+---+---+---+|...|...|...||...|4.9|.7.||.87|316|...|+---+---+---+|.39|...|72.||..8|...|31.||.15|...|89.|+---+---+---+|..1|763|98.||..3|1.8|56.||...|...|...|+---+---+---+  30C`

JPF
JPF
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Location: Paris, France

Re: More Homework 4

Code: Select all
`+---+---+---+|...|...|...||..2|34.|...||.36|.8.|59.|+---+---+---+|.58|...|7..||.7.|...|93.||...|...|84.|+---+---+---+|..3|598|.1.||.94|.31|2..||...|...|...|+---+---+---+     26C`
coloin

Posts: 2283
Joined: 05 May 2005
Location: Devon

Re: More Homework 4

slowly...
Code: Select all
`+---+---+---+|...|...|...||...|123|4..||.56|7..|8..|+---+---+---+|.73|...|58.||...|...|73.||...|...|...|+---+---+---+|.28|.9.|36.||.6.|41.|.9.||...|...|...|+---+---+---+   23C`

JPF
JPF
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Posts: 6017
Joined: 06 December 2005
Location: Paris, France

Re: More Homework 4

Code: Select all
`+---+---+---+|...|...|...||..2|34.|.7.||.36|1.2|5..|+---+---+---+|.58|...|...||.7.|...|93.||...|...|.4.|+---+---+---+|.2.|.79|.8.||..4|.6.|1..||...|...|...|+---+---+---+ 22C`
coloin

Posts: 2283
Joined: 05 May 2005
Location: Devon

Re: More Homework 4

Code: Select all
` . . . . . . . . . . . . 3 4 . . 7 . . 3 6 1 . 2 5 . . . 7 8 . . . . . . . 5 . . . . 3 2 . . . . . . . . 4 . . 2 . . 7 9 . 8 . . . 4 . 6 . 1 . . . . . . . . . . .   21C`

Mike

m_b_metcalf
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Location: Berlin

Re: More Homework 4

Code: Select all
` . . . . . . . . . . . 1 2 . . . 7 . . . 9 1 . 8 4 . . . 7 8 . . . . . . . 5 . . . . 9 2 . . . . . . . . 3 . . 2 . . 7 4 . 5 . . . 4 . 8 . 1 . . . . . . . . . . .  20C`

Mike

m_b_metcalf
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Posts: 13322
Joined: 15 May 2006
Location: Berlin

Re: More Homework 4

Code: Select all
`+---+---+---+|...|...|...||...|1.2|3..||.4.|..5|.6.|+---+---+---+|.52|...|1..||...|...|73.||...|...|...|+---+---+---+|.13|.8.|2..||.8.|.64|.5.||...|...|...|+---+---+---+   19C`

JPF
JPF
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Posts: 6017
Joined: 06 December 2005
Location: Paris, France

Re: More Homework 4

Code: Select all
`+---+---+---+|...|...|...||...|1..|2..||.3.|..4|.5.|+---+---+---+|..2|...|6..||.4.|...|.7.||..8|...|1..|+---+---+---+|..1|2..|8..||.5.|.37|.4.||...|...|...|+---+---+---+    18C`

Does anyone want to check that there is no 17C ?

JPF
JPF
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Joined: 06 December 2005
Location: Paris, France

Re: More Homework 4

So: Scan the 49158 17C db for an empty Box en 2 empty rows and 2 empty columns that doe not intersect that box.
And the 2 rows/columns must be in different bands/stacks. Right?

Hajime

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Joined: 20 April 2018
Location: Fryslân

Re: More Homework 4

JPF wrote:Does anyone want to check that there is no 17C ?

My attempt came up with none. Here's a near miss:
Code: Select all
` . . . . . . . . . . 5 . . 2 3 . . . . . . . 8 . 1 . . . 2 . . . . . 5 . . . 7 9 . . . . . . . 6 1 . . . . . . 3 . . 5 . . 2 . . . 1 4 . . 6 . . . . . . . . . . .  17C, B5 not empty`

There are none with only one clue in B5.

m_b_metcalf
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Location: Berlin

Re: More Homework 4

Right, there are no 17C-puzzles with 1 empty box + 2 empty rows + 2 empty columns.

Keeping the Minlex form:
There are 20 puzzles with 1 empty box + 2 empty rows + 1 empty column (up to a 90°-rotation)
Here is an example:
Code: Select all
`+---+---+---+|...|...|...||...|...|.12||...|.34|...|+---+---+---+|...|...|...||...|..5|4.6||.12|7..|...|+---+---+---+|...|.4.|8..||..6|2..|...||.95|...|3..|+---+---+---+`

There are 2 puzzles with 3 empty rows + 2 empty columns (up to a 90°-rotation)
Code: Select all
`+---+---+---+   +---+---+---+|...|...|...|   |...|...|...||...|..1|..2|   |...|..1|..2||..3|...|.4.|   |..3|...|.4.|+---+---+---+   +---+---+---+|...|...|...|   |...|...|...||...|34.|.5.|   |..4|.5.|.3.||.1.|.6.|..7|   |.6.|..2|..1|+---+---+---+   +---+---+---+|...|...|...|   |...|.3.|.5.||..4|..5|.3.|   |.1.|...|.76||.7.|8.2|..1|   |.2.|..8|...|+---+---+---+   +---+---+---+`

JPF
JPF
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Joined: 06 December 2005
Location: Paris, France

Re: More Homework 4

Well done on finding that 18 ...

Not sure how many clues we can remove from this next pattern challenge !

Code: Select all
`+---+---+---+|...|...|...||...|...|..2||.23|156|98.|+---+---+---+|.84|239|17.||.79|581|32.||.31|647|85.|+---+---+---+|.52|378|46.||7..|...|...||...|...|...|+---+---+---+  37C`

Code: Select all
`+---+---+---+|...|...|...||...|...|..2||.23|156|98.|+---+---+---+|.8.|23.|17.||.79|5..|3..||...|64.|.5.|+---+---+---+|.52|3.8|4..||7..|...|...||...|...|...|+---+---+---+  26C`
coloin

Posts: 2283
Joined: 05 May 2005
Location: Devon

Re: More Homework 4

Code: Select all
` . . . . . . . . . . . . . . . . . 2 . . 3 1 5 6 . 8 . . . 4 . . 9 1 . . . . 9 . 8 . . 2 . . 3 . 6 . 7 8 5 . . 5 2 3 . . 4 . . 7 . . . . . . . . . . . . . . . . .   22C, straight off`

m_b_metcalf
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Posts: 13322
Joined: 15 May 2006
Location: Berlin

Re: More Homework 4

Code: Select all
` . . . . . . . . . . . . . . . . . 7 . . 7 1 2 8 . 9 . . . 6 . . 9 3 . . . . 9 . 8 . . 4 . . . . 7 . 4 5 8 . . 5 2 3 . . 1 . . 4 . . . . . . . . . . . . . . . . .    21C`

No more time.

m_b_metcalf
2017 Supporter

Posts: 13322
Joined: 15 May 2006
Location: Berlin

Re: More Homework 4

Code: Select all
`+---+---+---+|...|...|...||...|...|..1||.2.|3.4|.5.|+---+---+---+|.6.|.1.|7..||.8.|..5|64.||..5|.79|.2.|+---+---+---+|..7|.91|...||4..|...|...||...|...|...|+---+---+---+   20C`

JPF
JPF
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Location: Paris, France

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