Need Help

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

Need Help

I'm stuck:

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`+----------------+----------------+----------------+ | 35   358  358  | 4    7    1    | 6    2    9    | | 9    4    6    | 3    58   2    | 178  57   15   | | 7    2    1    | 68   9    568  | 38   4    35   | +----------------+----------------+----------------+ | 356  3578 358  | 678  1    9    | 2    57   4    | | 56   9    2    | 67   3    4    | 17   8    156  | | 1    78   4    | 5    2    68   | 37   9    36   | +----------------+----------------+----------------+ | 4    1    35   | 2    58   358  | 9    6    7    | | 2    6    9    | 1    4    7    | 5    3    8    | | 8    35   7    | 9    6    35   | 4    1    2    | +----------------+----------------+----------------+`
mardyfan

Posts: 2
Joined: 01 January 2006

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`Consider the chain r4c2~5~r9c2-5-r7c3~5~r7c5-5-r2c5~5~r2c8-5-r4c8.When the cell r4c2 contains the value 5, so does the cell r4c8 - a contradiction.Therefore, the cell r4c2 cannot contain the value 5.- The move r4c2:=5 has been eliminated.Consider the chain r3c6-6-r6c6-<8|3>-r6c9-<6|5>-r3c9.When the cell r3c6 contains the value 5, so does the cell r3c9 - a contradiction.Therefore, the cell r3c6 cannot contain the value 5.- The move r3c6:=5 has been eliminated.The cell r3c9 is the only candidate for the value 5 in Row 3.`

I'm not sure whether the elimination provided by the first chain is strictly necessary in order to solve the puzzle.

BTW, personally I find it helpful if the puzzle is included in the post alongside the candidate grid. Thanks.
rubylips

Posts: 149
Joined: 01 November 2005

you can use Almost locked sets xz rule http://forum.enjoysudoku.com/viewtopic.php?t=2510
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`+----------------+----------------+----------------+| 35   358  358  | 4    7    1    | 6    2    9    | | 9    4    6    | 3    58   2    | 178  57   15   | | 7    2    1    |^68   9    568  |^38   4    35   | +----------------+----------------+----------------+| 356  3578 358  | 678  1    9    | 2    57   4    | | 56   9    2    | 67   3    4    | 17   8    156  | | 1   *78   4    | 5    2   *68   |*37   9    36   | +----------------+----------------+----------------+| 4    1    35   | 2    58   358  | 9    6    7    | | 2    6    9    | 1    4    7    | 5    3    8    | | 8    35   7    | 9    6    35   | 4    1    2    | +----------------+----------------+----------------+ A={R3C4,R3C7}B={R6C2,R6C6,R6C7}x=3z=6`

and you get both R5C4 and R4C4 are <>6
bennys

Posts: 156
Joined: 28 September 2005

Thank you for the tips mates !! Exactly what I needed.
mardyfan

Posts: 2
Joined: 01 January 2006