Help with EA Games Sudoku App on iPhone level 'insane'

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Help with EA Games Sudoku App on iPhone level 'insane'

Postby julnjake » Mon Oct 15, 2012 2:17 am

Can someone help with first big number please?
Thanks!
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Re: Help with EA Games Sudoku App on iPhone level 'insane'

Postby 7b53 » Mon Oct 15, 2012 5:24 am

cute puzzle to do without pencil markings.
wonder how long it takes to spot the triple of (1,4,9) at column 4.

easier to spot the pair of (1,5) at box 8. (r7c5 and r9c4=pair of 1,5)
first number... r6c4=3 (unique in column 4)
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Re: Help with EA Games Sudoku App on iPhone level 'insane'

Postby julnjake » Mon Oct 15, 2012 11:58 am

There is an option to put in candidates I just don't use it. Guess I have to do more reading on solving tips because I don't understand how you figured that out. Thanks though! And btw I love the app!!!!!
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Re: Help with EA Games Sudoku App on iPhone level 'insane'

Postby JasonLion » Mon Oct 15, 2012 1:19 pm

You need pencil marks, either written down or memorized, to solve a puzzle at this difficulty level. Once all of the valid pencil marks are known, solving it isn't all that difficult, requiring locked candidates and either a naked triple or a hidden pair.
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Re: Help with EA Games Sudoku App on iPhone level 'insane'

Postby ArkieTech » Tue Oct 16, 2012 12:40 pm

Code: Select all
 *-----------*
 |..7|A3.|.9.|
 |3..|A.5|2..|
 |...|A.2|8..|
 |---+---+---|
 |.4.|...|3..|
 |...|8.1|...|
 |..6|...|.5.|
 |---+---+---|
 |..8|6C.|...|
 |..5|7..|..1|
 |.9.|B2.|4..|
 *-----------*

AAA cannot contain the value 8 or 6
so it must contain 149

this means B cannot be a 1

so C must be a 1

since the three cells marked A must contain only three values it is called a locked set
the values 149 cannot appear anywhere else in the fourth column or second box.
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Postby Pat » Thu Oct 18, 2012 1:43 pm

julnjake wrote:There is an option to put in candidates,
I just don't use it

this puzzle can be solved without lists of "candidates"

as 7b53 pointed out,
b8 has a "hidden" duo {1,5}
which solves the c4 3

or going to a trio --
  • in b2, "hidden" trio {6,7,8} solves the c5 1
  • or in c4, "hidden" trio {2,3,5} solves b8 1

    Code: Select all
     . . 7 | . 3 . | . 9 .
     3 . . | . . 5 | 2 . .
     . . . | . . 2 | 8 . .
    -------+-------+------
     . 4 . | . . . | 3 . .
     . . . | 8 . 1 | . . .
     . . 6 | . . . | . 5 .
    -------+-------+------
     . . 8 | 6 . . | . . .
     . . 5 | 7 . . | . . 1
     . 9 . | . 2 . | 4 . .
if you list the possibilities in each cell,
you may notice the c4 "naked" trio ={1,4,9} ( instead of the c4 "hidden" trio )
-- which would give the same result
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Re: Help with EA Games Sudoku App on iPhone level 'insane'

Postby 7b53 » Thu Oct 18, 2012 8:10 pm

or going to a trio --
  • in b2, "hidden" trio {6,7,8} solves the c5 1
  • or in c4, "hidden" trio {2,3,5} solves b8 1

    Code: Select all
     . . 7 | . 3 . | . 9 .
     3 . . | . . 5 | 2 . .
     . . . | . . 2 | 8 . .
    -------+-------+------
     . 4 . | . . . | 3 . .
     . . . | 8 . 1 | . . .
     . . 6 | . . . | . 5 .
    -------+-------+------
     . . 8 | 6 . . | . . .
     . . 5 | 7 . . | . . 1
     . 9 . | . 2 . | 4 . .
if you list the possibilities in each cell,
you may notice the c4 "naked" trio ={1,4,9} ( instead of the c4 "hidden" trio )
-- which would give the same result


nice alternative ways to spot them.
either {2,3,5} at Box 2 toward column 4
or at column 4 {6,7,8} to Box 2

one can spot these triples in no time.

cheers
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