Post the puzzle or solving technique that's causing you trouble and someone will help

036|090|210
027|010|009
090|520|008

752|649|831
048|070|052
013|852|000

200|064|003
300|080|100
009|030|700

Thanks
fissh

Posts: 3
Joined: 08 June 2005

Are you sure you copied your grid correctly?

This puzzles requires a guess... (which means it is not a Pappocom puzzle)... where did you get it?

The guess you need: try to fill in 5 in r8c6. It will lead to an empty cell... (or twice the number 5 on row 8)
Animator

Posts: 469
Joined: 08 April 2005

I generate the puzzle with: http://act365.com/sudoku/

The solution is: (but I don't understand - no logic) record marked with ***

1. The value 5 in Box [3,1] must lie in Column 3.
The value 6 in Box [3,1] must lie in Column 2.
The value 8 in Box [3,1] must lie in Column 2.
The values 3, 6 and 7 occupy the cells (3,6), (3,7) and (3,8) in some order.
The value 4 in Box [1,1] must lie in Row 3.
The values 2 and 9 occupy the cells (8,4) and (8,8) in some order.
The cell (1,9) is one of 2 candidates for the value 4 in Row 1.
************************************************************
********* 2. The value 6 is the only candidate for the cell (2,8). ******
************************************************************
3. The value 7 is the only candidate for the cell (1,4).
4. The value 8 is the only candidate for the cell (1,6).
5. The value 3 is the only candidate for the cell (2,6).
6. The value 5 is the only candidate for the cell (2,7).
7. The value 9 is the only candidate for the cell (7,7).
8. The value 1 is the only candidate for the cell (7,4).
9. The value 6 is the only candidate for the cell (5,7).
10. The value 8 is the only candidate for the cell (7,8).
11. The value 2 is the only candidate for the cell (8,8).
12. The value 5 is the only candidate for the cell (9,6).
13. The value 4 is the only candidate for the cell (9,8).
fissh

Posts: 3
Joined: 08 June 2005

The cell (1,9) is one of 2 candidates for the value 4 in Row 1.

This line shows that the program took a "guess". It tried one of the two possibilities without any particular reason for choosing one over the other.
Last edited by simes on Sun Dec 11, 2011 2:37 pm, edited 1 time in total.
simes

Posts: 324
Joined: 11 March 2005
Location: UK

fissh wrote:
Code: Select all
` . 3 6 | . 9 . | 2 1 .  . 2 7 | . 1 . | . . 9  . 9 . | 5 2 . | . . 8 -------+-------+------ 7 5 2 | 6 4 9 | 8 3 1  . 4 8 | . 7 . | . 5 2  . 1 3 | 8 5 2 | . . . -------+-------+------ 2 . . | . 6 4 | . . 3  3 . . | . 8 . | 1 . .  . . 9 | . 3 . | 7 . . `

if r8c6 = 5
then r7c3 = 5, r7c4 = 1, and r9c6 has no possibility remaining

Pat

Posts: 3641
Joined: 18 July 2005