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 Post subject: MeanDoku
PostPosted: Tue May 30, 2017 10:39 am 
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Grand Master
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Joined: Wed Apr 30, 2008 9:45 pm
Posts: 531
A new variant see:

http://forum.enjoysudoku.com/post257549.html#p257549

my first attempt is not too difficult - I'll improve it and post here.


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 Post subject: Re: MeanDoku
PostPosted: Thu Jun 01, 2017 4:09 pm 
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Grand Master
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Joined: Wed Apr 30, 2008 9:45 pm
Posts: 531
MeanDoku 2H

I've removed some clues (from MeanDoku 2) - mainly equality as those are the most helpful.

This is a pleasant puzzle type - but it is easy to make mistakes.

I found the trapezoids difficult to see clearly so I have gone for colours:
Green: the average of the two adjacent cells is below five
Blue: the average of the two adjacent cells is five
Red: the average of the two adjacent cells is above five

NC: horizontally and vertically adjacent cells are non-consecutive.

Image

Solution:

915738246
647295813
382641597
869473152
531826974
274159638
426917385
158364729
793582461


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 Post subject: Re: MeanDoku
PostPosted: Tue Jun 13, 2017 1:13 am 
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Addict
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Joined: Mon Apr 21, 2008 11:35 pm
Posts: 28
Really enjoyed this one, Hatman! Thanks!

Printed out your V2 and the very difficult-looking 3. Will give those a go.

(Am I wrong in thinking that a run-thru on these would be extremely long and difficult?)


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 Post subject: Re: MeanDoku
PostPosted: Sun Jun 18, 2017 5:43 pm 
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Master
Master

Joined: Tue Jun 16, 2009 9:31 pm
Posts: 148
Location: California, out of London
Thanks HATMAN! I found this new puzzle type quite tricky to get going, until I realized some implications of the puzzle rules which allowed me to think about it clearly.
Here's how I did it after that.
MeanDoku II - WT:
Implications from the puzzle rules:

(I1) A 1 cannot be on any cell with a Red Mark (RM), or a 9 in any cell with a Green Mark (GM). A 2 can have at most one RM (and that with a 9), etc.
(I2) Since the puzzle is NC - each GM must have at least one of (123) in the cells it straddles.
Similarly a RM must have at least one of (789) in the cells it straddles.
(I3) A Blue Mark (BM) must have one number smaller than 5 and one number larger than 5 in the cells it straddles.

1. n9
of the numbers (789)...
(I2) -> One in r89c7, one in r8c89
(I2) -> One in r7c8
(I3) -> One in r8c9

-> r8c8 and r9c9 both from (123)
-> r9c8 not from (123)
(I1) -> HS 1 in n9 -> r9c9 = 1
-> r8c9 = 9
-> HS 2 in n9 -> r8c8 = 2
-> r7c8 = 8
-> 7 in r89c7
-> 3 in r7c79

2. n8
(I1) -> HS 1 in n8 -> r7c5 = 1
(I2) One of (789) in r78c4, one in r78c6
(I2) -> one of (78) in r9c5. (Cannot be 9 since r9c56 cannot be [91])
-> 9 in r7c46
-> HS 2 in n8 -> 9c6 = 2
-> r9c5 = 8

3. n6
(I1) -> 1 in r4c78
8 in r7c8 -> r6c8 not from (789)
(I2) -> r6c9 from (78)
-> r5c9 not from (789)
(I2) -> r5c8 from (789). Only possibility is 7.
-> r56c8 = [73]
-> r6c9 = 8
(I1, I2) -> r5c7 = 9
r5c9 at least 4 -> (I2,NC) r4c79 = [12]
(NC) -> r6c7 = 6
-> r4c8,r5c9 = {45}

4. n3
(28) both in r123c7 -> r12c7 = {28}
(I1) -> 1 in r12c8 (adjacent to the 8)
(I1) -> r3c8 = 9
Since r3c9 is max 7 -> r2c9 is min 3
-> r1c9 is max 6
Also r1c9 is min 3 -> r2c9 is max 6
-> HS 7 in n3 -> r23c9 = [37]

5. c123
(I1) -> r8c3 = 8
(I1) -> r9c2 = 9
Also (I1, NC) -> r4c13 = [89]
-> r5c3 = 1
(I2) One of (789) in each of r12c1, r12c3, and r3c2
They can only be in that order 9,8,7
(I1) -> r1c2 = 1 -> r1c1 = 9
Also HS r6c2 = 7

6. Some more...
HS r2c8 = 1
-> r12c7 = [28]
-> (NC) -> r1c89 = [46], r3c7 = 5
-> r1c45 = {37}
-> r2c3 = 7
-> r1c36 = [58]
Also r9c8 = 6
-> r8c7 = 7, r7c9 = 5, r9c7 = 4
-> r4c8 = 5, r5c9 = 4
etc.


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 Post subject: Re: MeanDoku
PostPosted: Tue Jun 20, 2017 11:18 am 
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Grand Master
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Joined: Wed Apr 30, 2008 9:45 pm
Posts: 531
Wellbeback

My general approach to this puzzle type has been (I've been solving them in JSudoku.):
enter 10(2) cages around all blue squares
1-9 run: clear 1 from reds, clear 9 from greens - solve out
23-78 run: clear 2 from two reds and 3 from three reds, clear 8 from 2 greens and 7 from 3 greens - solve out
consider cells with red and green: cannot be too high or low
consider nonets with almost all clues for interactions


Maurice


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