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Checking completed puzzles

 
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Marty R.



Joined: 12 Feb 2006
Posts: 5164
Location: Rochester, NY, USA

PostPosted: Wed Mar 22, 2006 6:00 pm    Post subject: Checking completed puzzles Reply with quote

When I finish a puzzle, I scan each row, then each box to make sure there are no duplicates. Is it also necessary to scan each column? Or is checking just one of the groups (row-column-box) adequate?
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keith



Joined: 19 Sep 2005
Posts: 3179
Location: near Detroit, Michigan, USA

PostPosted: Thu Mar 23, 2006 1:02 am    Post subject: Why bother? Reply with quote

Marty,

If you make a mistake, you will notice it long before you complete the puzzle. I do not bother to check completed puzzles.

If you feel you must check, then you must check blocks, rows AND columns. Here is why:

Start with a completed correct puzzle. Interchange two numbers that are in the same row and block. The row and block will still have 1 - 9, the only way to find this "mistake" is to look at the columns.

Keith
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Marty R.



Joined: 12 Feb 2006
Posts: 5164
Location: Rochester, NY, USA

PostPosted: Thu Mar 23, 2006 5:50 pm    Post subject: Reply with quote

Thanks for the explanation Keith.
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