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10 March 2009 @ 08:48 am
3/10/09 - Almost Perfect  
Difficulty: Easier 5x5 KenKen



I spent some time this weekend while waiting for my ride up to SF for Iron Puzzler searching for a "just one value" puzzle that would work without operators. I got very very close, especially when I moved from a 5x5 with just 8s to a 5x5 with just 10s. I'm not there yet (this example has ~3 answers if I drop the operations), but the above puzzle has a good difficulty level and a fairly elegant theme for a Tuesday puzzle. (Note: the early posting of this puzzle had a formatting problem, so be sure the order of operations in the second row is 10+ and then 10x)
 
 
( 4 comments — Post a new comment )
[info]ericberlin on March 10th, 2009 07:33 pm (UTC)
I did not find this easier then your past KenKens, but I suspect there are many tricks of the trade I have yet to learn.
motris[info]motris on March 10th, 2009 10:54 pm (UTC)
Well, I hope you had the corrected version of the image (with a 10+ and then a 10x on the second row) as the one with 10x and then 10+ that was mistakenly posted had 2 answers. A mix-up in transferring files from my laptop (currently in for repairs) and my main computer caused the problem and an incorrect puzzle was up for about 30 minutes.

The solution here includes steps like "all cells but one are being used in a row/column" which are fairly common as entry points in Killer Sudoku under the name innies/outies but maybe are more rare when used in KenKen where unique valuations in 2-cell cages are more common. This can get you started both in the first row, and soon after, the fifth column. My rating system is probably also not well calibrated yet as I haven't watched dozens of other people solving KenKen on airplanes and buses and the like (which helped when I learned how to rate Sudoku difficulties well given different human approaches), so don't take the Easier label too strongly.
[info]ericberlin on March 11th, 2009 01:12 am (UTC)
I either had the wrong puzzle or a complete shutdown of several brain lobes, because my second time through I solved it in about two minutes.
cyrebjr[info]cyrebjr on March 11th, 2009 03:44 am (UTC)
Is the rule "pics or it didn't happen"? Anyway, walkthrough.

First, by the law of leftovers, R1C5=5. And since 5 is a prime factor of 10, 5=R4C4=R2C3, while R4C5=2.

Next, LoL on R45 says R4C2=3, and on C5 says R5C5=3. Since R23C4=12, R15C4 is left with 34, meaning R1C4=3 and R5C4=4. The two remaining 3's in R23C13 can be placed: R2C1 and R3C3.

Now, 4 is too big for R4C3, so it's 1 and R4C1=4. The next few just drop in: R5C3=2, R1C3=4, R3C2=4. The last 4 goes in R2C5, and the rest follows automatically.
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