The New Sudoku Players' Forum

by **daj95376** » Sun Jul 30, 2006 6:19 am

Code: Select all: 9...1.......2.3.8...8...7...2.....3.4...6...1.6.....5...3...6...1.8.7.......4...5 r1c6 = 8 Hidden Single r4c9 = 6 Hidden Single b8 - 6 Locked Candidate (1) r2 - 6 Locked Candidate (2) c9 - 2349 Naked Quad b6 - 4 Locked Candidate (1) r7c2 <> 8 Templates -- Pass C (Multi-Colors in Simple Sudoku)

I get this far with Basic Techniques.

Code: Select all: *--------------------------------------------------------------------* | 9 3457 2457 | 4567 1 8 | 235 246 234 | | 1567 457 14567 | 2 579 3 | 159 8 49 | | 1235 345 8 | 4569 59 4569 | 7 12469 2349 | |----------------------+----------------------+----------------------| | 1578 2 1579 | 14579 5789 1459 | 489 3 6 | | 4 35789 579 | 3579 6 259 | 289 279 1 | | 1378 6 179 | 13479 23789 1249 | 2489 5 78 | |----------------------+----------------------+----------------------| | 2578 4579 3 | 159 259 1259 | 6 12479 78 | | 256 1 24569 | 8 2359 7 | 239 249 2349 | | 278 789 279 | 1369 4 1269 | 12389 1279 5 | *--------------------------------------------------------------------*

At this point, I want to show that [r1c3]=2 using the chain below.

Code: Select all: [r1c3]=2=[r3c1]=1=[r3c8]-1-[r79c8] =3=[r6c1]-3-[r6c45]=3=[r5c4]-3-[r9c4]=3=[r9c7]

This results in [b9]=INVALID (no 1s) and I get the contradiction I need.

Is there a simple way to show this chain and the resulting contradiction?

by **ravel** » Sun Jul 30, 2006 12:06 pm

A bit simpler is to write it in a closed chain:
r3c1=2 => r3c8=1 => r2c7<>1 => r9c7=1 => r9c4=3 => r8c5<>3 => r6c5=3 => r6c1<>3 => r3c1=3

by **claudiarabia** » Sun Jul 30, 2006 2:02 pm

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

Claudia

by **daj95376** » Sun Jul 30, 2006 4:13 pm

ravel wrote:A bit simpler is to write it in a closed chain:
r3c1=2 => r3c8=1 => r2c7<>1 => r9c7=1 => r9c4=3 => r8c5<>3 => r6c5=3 => r6c1<>3 => r3c1=3

Thanks ravel !!! I'll study this and use it in the future.

by **udosuk** » Sun Jul 30, 2006 5:12 pm

Code: Select all: *--------------------------------------------------------------------* | 9 3457 2 | 4567 1 8 | 35 46 34 | | 1567 457 46 | 2 579 3 | 159 8 49 | | 135 345 8 | 4569 59 4569 | 7 12469 2349 | |----------------------+----------------------+----------------------| | 78 2 1579 | 14579 5789 1459 | 489 3 6 | | 4 3789 579 | 3579 6 259 | 289 279 1 | | 378 6 179 | 13479 23789 1249 | 2489 5 78 | |----------------------+----------------------+----------------------| | 2578 4579 3 | 159 259 1259 | 6 12479 78 | | 256 1 46 | 8 2359 7 | 239 249 2349 | | 278 789 79 | 1369 4 1269 | 12389 1279 5 | *--------------------------------------------------------------------* r7c2=9 => r9c3=7 => r9c2=8 => r9c1=2 => r7c1=5 => r7c456={125}

How to represent this nicely?

by **ronk** » Sun Jul 30, 2006 6:54 pm

udosuk wrote:How to represent this nicely?

Using the ALS xz-rule:

Code: Select all: Sets: A = {r7c1,r9c123} = {25789} B = {r7c456} = {1259} x = 5, z = 9 implies r7c2<>9, r9c46<>9

by **udosuk** » Mon Jul 31, 2006 4:18 am

Thanks ronk (#1)!

Will try to learn this technique... Are there simpler methods for this puzzle?

Just realised it's like a "grouped wxyz-wing":

r7c2=9 or r9c46=9 => r7c456={125} & r9c123={278} => nothing left for r7c1

by **ravel** » Mon Jul 31, 2006 2:18 pm

I dont know, if someone here plays my p&p puzzles, which need a bit more than basics, but are not harder, if you know x-, xy-, xyz-wing, UR type 1,2,4 and turbot fish (all easier to spot than some naked triples).
But my friend, who is pure p&p solver (and much faster than me), likes them, because she does not need much pencilmarks. So i continue with some faces:

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

For copying:

Code: Select all: ..........63...21.4..6.8..91..5.2..6.47...18..............1.....56...43....369... ..........41...79.2..9.8..61..5.7..2.29...63.....................54619...9.....5. ..........61...39.2..9.8..11..5.7..2.24...97............9.6.7....8...1.....743... ..........41...26.2..6.1..55..2.9..3.64...85.............394.....2...9....8.6.1.. ..........47...26.6..4.8..51..6.2..9.39...87.............379.....5...4.....564... ..........17...65.2..3.9..77..1.2..6.23...49..........1.......9.4.....7....423...

With 2x BUG lite:

Code: Select all: ..........31...78.4..5.6..29..3.1..8.68...15.............875.....5...3.....693...

With UR3:

Code: Select all: ..........39...46.4..7.5..33..8.6..4.92...75.............183.....1...9.....469...

by **JPF** » Tue Aug 01, 2006 1:30 pm

How many solutions ?

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

JPF

by **udosuk** » Tue Aug 01, 2006 3:01 pm

(Classical) Sudoku is a puzzle about:

Code: Select all: . # # # # # # # . # # # # # # # # # # # . . . . . # # # # . . . . . # # # # # # # # # # # . # # # # # # # # . . . . . . . # # # # # # # # # # # . # # # # # # # .

Anyone?

by **JPF** » Tue Aug 01, 2006 10:34 pm

udosuk wrote:(Classical) Sudoku is a puzzle about:
Code: Select all
. # # # # # # # . # # # # # # # # # # # . . . . . # # # # . . . . . # # # # # # # # # # # . # # # # # # # # . . . . . . . # # # # # # # # # # # . # # # # # # # .

Anyone?

You mean : the boss ?

JPF

by **udosuk** » Wed Aug 02, 2006 5:01 am

I don't think the boss will take up this challenge... It's you I'm counting on...

With so many filled cells, is it hard to construct a puzzle with that number of solutions? :?:

by **JPF** » Wed Aug 02, 2006 7:27 am

udosuk wrote:With so many filled cells, is it hard to construct a puzzle with that number of solutions?

Yes it is.
With your proposed shape, 4 solutions seems to be the maximum.

JPF

by **ravel** » Wed Aug 02, 2006 11:24 am

Three patterns:

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

The last one is a bit harder (BUG lite, UR type3).

by **claudiarabia** » Sun Aug 06, 2006 7:00 pm

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

Claudia

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