View unanswered posts | View active topics It is currently Thu Jul 24, 2014 4:58 pm



← Back to the Calcudoku puzzle page




Reply to topic  [ 3 posts ] 
 Step by step solution of an 9x9 
Author Message

Posted on: Wed Nov 30, 2011 4:35 pm




Posts: 248
Location: Lisbon, Portugal
Joined: Sun Sep 18, 2011 3:40 pm
Post Step by step solution of an 9x9
I beg your goodwill to the presentation of this puzzle. It's my first one
and also the first contact with the tools used. Anyway I thank for your critiques,
opinions, alternative steps and suggestions.

I limited the most the text and pretended that the "step by step" was exactly
a "step by step" exhaustive and complete for other begginers (save the obvious).


I advise the eventual interested to draw the diagram and to accompany, writing
everything on the paper.

And now, as almost always, I'm sorry for my English ( To write this text
I consulted the dictionary 8 times ).

Image

Uploaded with ImageShack.us




1) green
2) yellow: "192*"=[4,6,8]
3) brown: "1008x"=[2,7,8,9]
4) blue
5) grey: "252*"=[1,4,7,9]

Image

Uploaded with ImageShack.us



6) green: Analysing row 6 : "48*"<<>>7, "2880x"<<>>7 --> e1=7.
"280*"=[1,5,7,8],[2,4,5,7].
"48#"=[2,3,8],[3,4,4].
Analysing column 8 --> h6=9.
Analysing row 6 --> b6=7.


7) yellow: h5=1 --> c5=8,c4=1.
"4-"(a4)=[2,3,9],[1,4,9]. c4=1 -->"4-"=[2,3,9].
"2-"=[2,4],[3,5]. a6=2,3,4,8, i6=2,3,4,8.


8) brown: "2880x"=[1,5,8,8,9],[2,4,5,8,9].


9) "6-"=[1,7],[2,8]. h7=8 and i7=1 --> "2880x"<<>>[1,5,8,8,9]

--> "2880x"=[2,4,5,8,9].

10) There should be a 8 in the column h of "192x" and in the column i of "2880x",

i.e. "192x"(hhhh) and "2880x"(iiii) or vice versa. Then, all the other 8s of those

columns must disappear. So h9<>8, i9<>8 --> g9=8.


Image

Uploaded with ImageShack.us


11) In the column i it lacks (1,3).

So "4-"(i2)=[x,1],[x,3] --> "4-"(i2)=[1,5],[3,7]

and "4-"(i2)(+)=[6,10].


(h+++)+(i+++)= 45+45= 90. Knowing the sum of all the cages of the two columns,

"2880x"(+)=2+4+5+8+9=28 and so on, we have:

85 + "4-"(i2)(+) + h2 - g9=90 --> h2 + "4-"(i2)(+) = g9 +5 "4-"(i2)(+)=[6,10].

If (4-)(i2)(+) = 6 --> h2=7 unique possibility

If (4-)(i2)(+) = 10 --> h2=3 impossible

After this h2=7, g2=5, [f1,g1]=[2,4].


Image

Uploaded with ImageShack.us


12) green: h9=2, i9=7, h7=5

e5=5 --> f5=3, d5<>3 --> d5=[2,4] --> d6=[2,3,8],

e6=[2,4,8], h1=[6,8].



13) yellow: i4=6 --> h3=[4,8] --> h1=6.

i1=3 --> "4-"(i2)=[1,5] --> i2=1, i3=5.

a=[7], b=[7] --> e1=7.

"16+"=[7,1,8],[7,2,7],[7,3,6],[7,4,5] __> e2=3,f2=6, a2=9, b2=8, d2=2

-- > "48x"=[4,3,4], a6=[2,8], i6=[2,8]

g8=[4,7] --> g1=2, f1=4, b1=1, a1=8.



Image

Uploaded with ImageShack.us


14) green: a6=2, i6=8, i7=[2,4], a4=3, b4=2, b8=5, b9=4,

f9=1, f8=[4,7] --> c8=2, c7=7.


15) yellow: "112x"=[1,2,7,8] --> d3=7, e3=1, e4=8 --> f4=4,

f3=8 --> g4=7, g8=4, f8=7.


f=[...,2,8,9,...] --> "0-"=[2,9], f7=8, f6=2, i7=4,

"252x"=[1,2,3,6,7] --> a6=2, b7=3, a7=6, a8=1, a4=3, e8=6.



To complete now the puzzle, it is very simple.
The hardest of this puzzle is the number 11). If anyone uses a different method
I wolud like to know.

_________________
Visit http://www.calcudoku.org the most interesting and addictive site of puzzles.


Profile

Posted on: Wed Nov 30, 2011 5:57 pm




Posts: 36
Joined: Fri May 13, 2011 8:23 am
Post Re: Step by step solution of an 9x9
Quite a walkthrough jomapil! It's nice to have look at other solver's strategies...

About step 11,

You write column i lacks [1,3], this is true but also the columns h and i lack a 6 (image 2). Based on the information in that image 6 can only be in either h1 or i1, hence "9+"=[6,3]. Thus "4-"<> [7,3] but only "4-"=[1,5].

If I have correctly followed your walkthrough, does this help?


Profile

Posted on: Wed Nov 30, 2011 10:55 pm




Posts: 248
Location: Lisbon, Portugal
Joined: Sun Sep 18, 2011 3:40 pm
Post Re: Step by step solution of an 9x9
Good point and thank you, Honkhonk.
It's good to see other solutions, because they teaches us more tricks.
I hope more variations on my solution.

_________________
Visit http://www.calcudoku.org the most interesting and addictive site of puzzles.


Profile
Display posts from previous:  Sort by  
Reply to topic   [ 3 posts ] 

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to:  
cron
All forum contents © Patrick Min, and by the post authors.

Forum software phpBB © 2000, 2002, 2005, 2007 phpBB Group.
Designed by STSoftware.