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# Tough Sudoku for 22/January/2009

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Submitted by: sudoku lover

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 Cute! Cute! Cute! 22/Jan/09 12:07 AM Hi Mathman From Tigerland - re your question yesterday.I can think of two reasons for not being required to prove uniqueness when solving.1. If the rules state that the solution is unique and contains only numbers 1-9 once each in every column, row, box etc. Then you should be able to More... 22/Jan/09 12:35 AM Cute! 22/Jan/09 12:47 AM Hi Jimmy from Scotland, Thanks for your response to my comment. Having to prove uniqueness makes the puzzle more challenging and therefore, for me, more fun. (Perhaps a year from now I will agree with you!) As to the two points you raised, the first suggests a choice of ground rules, and More... 22/Jan/09 12:58 AM Who is there? Have a good day/night all of us 22/Jan/09 2:21 AM Waiting for someone special to return? Reminds me of my daughter waiting for her brother to to get home from school (we're talking 25 years ago). 22/Jan/09 4:40 AM 32:25 22/Jan/09 5:41 AM That was the first time she decided to pull herself up on anything. She was just looking to see the world outside. Man that seems SO long ago. We had to put those pants away a few months ago because they became high waters. She is now 17 m.o. and racing around everywhere. 22/Jan/09 6:27 AM 1. Note pair 38 at e2/f1. Unique possibilities: e8=1=h2,d9=7=f6,e3=9 (UP27).2. Locked 2s at ai59;so pair 38 at e25 make e7=4=f4,f5=5=d3,f3=1. (UP 32).3. When a2=5,a8=6=i1,g1=5. When a2=9,g1=9,a5=2,i5=3. So g1/i1 are never 3; This makes f1=3, and the rest is solved (UP 81). 22/Jan/09 7:32 AM 37:26 22/Jan/09 12:42 PM I was able to solve this in a without the step 3 when stuff. start22d9723e8124f4425e7426e3927f6728f3129d3530f5531 More... 22/Jan/09 1:06 PM 16:01 to you all from Beijing. I was able to solve this using elementary methods alone. 22/Jan/09 4:39 PM 17:49, hi all. 22/Jan/09 7:37 PM 38:29 Better late than never. (long time to solve plus a day late.) 23/Jan/09 10:59 AM 1)Start at 22,=>UP=272)XW(2):a5=a9-i9=i5,=>e5cg9<>2.UP=323)Loop:(9)h9=(hp19-2)ac9=(2)a5-(2=3)i5 -(3)h46=(3)h9=>c9<>34,g46<>3.=>np:bc8=344)(56=3)i18-(3=2)i5-(2=9)a5-(9=5)a2,=& gt;i2<>5.=>np:i18=565)(5=9)a2-(9)g2=(9-3)g1=(3)f1-(3)e2=(3)e5-(3=2)i5-(2=9)a5=>a2< ;>9.UP=81 23/Jan/09 1:26 PM SE=7.3 09/Sep/10 9:06 PM