colors-confused

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colors-confused

Postby lovethepirk » Thu Feb 23, 2006 8:15 am

Thanks in advance for your help...

I tutorialed this site to learn colors:
http://angusj.com/sudoku/hints.php

But the advice was pertaining to cells that only had two possible values.
This 'colors' step is dealing with more than that:(

***Sudoku from "Simple Sudoku" Expert Level

Image
I am confused as I am only used to 'colors' when there are only 2 values possible in each cell.
For instance...
Why is the suggestion here to eliminate 5's and not 4's?
What cell did you begin the first coloring in?
What was the tip off to use colors?

Any other info would be appreciated, as I am a newbie to this expert level, but I pick up
fast and really enjoy the tougher Sudokus.

Thanks,

LTP
lovethepirk
 
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Postby lovethepirk » Thu Feb 23, 2006 9:13 am

I think I got it...Let's see if this is correct...

Only color the number(5 in this case) that only have two possibilities per row/column.

So the only colors needed here would be this:
Image
And hence we see that b/c there are two greens in box 1 then they cannot be 5. So we see
that R2C3=>5 and the puzzle now solves itself.

Is this correct?

Also Does this method just eliminate the '5's from box 1 or does it say there must be a '5'
in R8C1(I know a 5 goes there through deduction but could I just throw one in there since it
is blue)?


LTP
lovethepirk
 
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Postby emm » Thu Feb 23, 2006 9:33 am

LTP wrote:Does this method just eliminate the '5's from box 1 or does it say there must be a '5' in R8C1
You mean r9c1.

LTP wrote:(I know a 5 goes there through deduction but could I just throw one in there since it is blue)?

Well, it's confusing because you switched the colours in the two posts. Take your second post. Colouring eliminates the 5s from box 1 because there are 2 greens - therefore all your greens are now false and the blues are true.

If you had coloured all the 5s - as in the first post - then you could have eliminated all five originally blue 5s.
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Postby TKiel » Thu Feb 23, 2006 12:27 pm

When two cells with the same color end up sharing a group, then you know that color must be false and the opposite color must be true. ALL the cells marked with the opposite color can be assigned the value 5.

Tracy
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Postby lovethepirk » Thu Feb 23, 2006 7:55 pm

TKiel wrote:When two cells with the same color end up sharing a group,


Does the word "group" in your statement mean a box as in this case or could it mean a row or column too?

Thanks,

LTP


And thank you to em for posting:)
lovethepirk
 
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Postby TKiel » Fri Feb 24, 2006 2:26 am

LTP,

Yes, in this case it means a box, but it could also mean a row or a column.

Tracy
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