The New Sudoku Players' Forum

[SpAce]

Code: Select all

....X2..5.
7.....X...
..X7......
.......X..
.X5.4.....
...X...5.6
4....7...X
2.3.6...X.
X.....2...
.....X....

Another non-trival Blocku. The solution is also unique without the 2 in r8c1 (I'm still working on a non t&e solution).

That was fun. Not hard at all, but took some time. In fact, I think I'll take a break from solving these because of the time drag. It's nice to solve on paper after a long time, but it's just so slow compared to Hodoku solving.

my solution: Show

Code: Select all

6 7 8 9 . 2 1 3 5 4
7 6 9 5 8 4 . 2 1 3
8 9 . 7 2 3 4 1 6 5
5 8 4 6 3 9 7 . 2 1
9 . 5 8 4 1 3 6 7 2
3 2 1 . 7 8 9 5 4 6
4 1 6 2 9 7 5 8 3 .
2 4 3 1 6 5 8 7 . 9
. 5 7 3 1 6 2 4 9 8
1 3 2 4 5 . 6 9 8 7

The decisive move was an X-Wing on 4s (stte after that). I also used three other X-Wings (2s, 8s, 1s) and a DP(123) before spotting that, but I don't know how much effect they had.

[Leren]

Code: Select all

....X2..5.
7.....X...
..X7......
.......X..
.X5.4.....
...X...5.6
4....7...X
..3.6...X.
X.....2...
.....X....

Same as the one above without the clue 2 in r8c1. Requires chains to solve. Leren

[koushanejad74]

Code: Select all

....X2..5.
7.....X...
..X7......
.......X..
.X5.4.....
...X...5.6
4....7...X
2.3.6...X.
X.....2...
.....X....

Another non-trival Blocku. Leren

Leren,

How did you generate this sample?

[SpAce]

Code: Select all

....X2..5.
7.....X...
..X7......
.......X..
.X5.4.....
...X...5.6
4....7...X
..3.6...X.
X.....2...
.....X....

Same as the one above without the clue 2 in r8c1. Requires chains to solve. Leren

Done. I used the same steps as before plus one loop and one chain.

my steps: Show

Step 1: X-Wing (8)c90\r90 => -8 r90
Step 2: X-Wing (2)r45\c90 => -2 c90
Step 3: X-Wing (1)r24\c90 => -1 c90
Step 4: DP(123)r245c90 => -23 r5c9
Step 5: X-Wing (4)r36\c79 => -4 c79
Step 6: (5'8=7)r8c67 - r4c7 = (7-3)r4c5 = (3-5)r4c1 = (5)r8c1 - loop => -5 r8c2, -8 r8c8, -7 r6c7, -589 r4c5
Step 7: (412=5)r8c421 - (53=7)r4c15 - (74)r6c59 = (469)r630c7 - (9=64)r09c8 => -4 r8c8; stte

(0 : the tenth row or column)

Thanks for this. I'd almost forgotten how good my p&p system is for chain spotting. With Hodoku I definitely would have had to use coloring, but not now. Of course I might have found something simpler if I'd resorted to coloring, but it was more fun this way. Feels more like real solving.

What steps did you have?

[Leren]

koushanejad74 wrote : How did you generate this sample?

I now have a Blocku solution counter and solver, based on my Str8s equivalent.

I make up black cell patterns and clues randomly and keep adding clues and/ or moving them around until I get a unique solution, which I then solve by normal methods.

Unless I have a bug in my newly minted code, not all complying black cell patterns admit of any solutions at all.

leren

[SpAce]

Still interested in this:

What steps did you have?

[Leren]

Code: Select all

.X.3......
.....X..8.
.3.7...X..
.4..X...5.
.....5.2.X
X9.8..7...
.5..7...X.
......X...
..X.6.....
...X......

Another non-trivial Blocku - requires chains and/or URs.

Leren

[SpAce]

Code: Select all

.X.3......
.....X..8.
.3.7...X..
.4..X...5.
.....5.2.X
X9.8..7...
.5..7...X.
......X...
..X.6.....
...X......

Another non-trivial Blocku - requires chains and/or URs.

Or one simple chain, no URs. (I also used one obvious X-Wing before that, but I don't think it was necessary.)

my solution: Show

Code: Select all

1 . 5 3 2 9 4 8 7 6
5 2 1 4 3 . 6 9 8 7
4 3 6 7 1 2 5 . 9 8
2 4 3 1 . 6 8 7 5 9
3 1 7 6 8 5 9 2 4 .
. 9 4 8 5 1 7 3 6 2
6 5 2 9 7 8 3 4 . 1
7 6 8 5 9 4 . 1 2 3
9 8 . 2 6 7 1 5 3 4
8 7 9 . 4 3 2 6 1 5

Step 0: X-Wing (1)r24\c34 => -1 r6c3,r9c4 (unnecessary, I think)

Step 1: (4)r5c9 = r1c9 - r1c7 = (4-5)r3c7 = (5,4)r32c1 => -4 r5c1; stte

Btw, I think I'm done with these for now. They're fun, but p&p solving is time-consuming. In other words, if I don't reply to further puzzles, it doesn't imply they were too hard. It just means I didn't try. If I do try, I will report back with either result. So far they've all been relatively easy.

[tarek]

I like the idea of the Blind Blocku where the blocks are also unknown. I will try to have a play at generating these.

I also like the idea of the Double Blind Blocku (Where any cell containing a number could be a block cell). If I achieved the above I may also do this one.

tarek

[Wecoc]

I was thinking a bit more about this, and I believe this one has only one solution.

Code: Select all

X.........
.X........
..X.......
...X......
....X.....
.....X....
......X...
.......X..
........X.
1........X