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17 December 2010 @ 12:24 am
Friday Puzzle #80 - A Booster Shot  
The last two weeks have gotten a fair number of comments - many positive, but many calling the puzzles "too easy". There are many good reasons to start slowly when constructing a new type of puzzle, or in introducing new types to an unfamiliar audience. One of my reasons is that I recently began to cross-post these puzzles on Wired's Decode blog (under the series title "Dr. Sudoku Prescribes") and I felt my sometimes brain-busting content was not the right way to start. Some puzzles, like the regular but easy Shikaku, were simply elegant solves even if the challenge was lower than usual. Well, I've revisited the themes of the last two weeks to offer this "booster shot" of puzzles. I still haven't taken these puzzles to crazy extremes, but here are (hopefully) more challenging versions of the recent Star Battle and Shikaku puzzles. Enjoy!

Star Battle:
Place stars into some cells in the grid so that each row, column, and region contains exactly two stars (in the example, just one star). Stars cannot be placed in adjacent cells, not even diagonally.



Shikaku Variant:
Divide the grid below into rectangles so that all cells belong to one rectangle and so that each rectangle contains one numbered circle. The numbered circle must indicate the area of the rectangle, not counting any of the gray cells, as seen in the following example.


MellowMelonMellowMelon [wordpress.com] on December 18th, 2010 07:05 pm (UTC)
The star battle was a nice repeated use of the same advanced technique. Quick if you knew it.

The shikaku I saw my way to the answer in about half a minute. I went back and did it logically, and it sure took a lot longer. I'm a bit ambivalent about the variation itself. It's true that it gets rid of the automatic "oh this 4 is 1x4 or 2x2" knowledge, but at times my deductions hinged on going through the possibilities of what rectangle could contain a number. It had a little bit of the drudge of doing a computer generated Kakuro and needing to brute force the possible sums of a number that's not something like a 5-cell 35, although not nearly that bad. I guess I still like the rule change overall though.
motrismotris on December 19th, 2010 04:45 pm (UTC)
I'm seeing that problem as I'm trying to construct them where now it takes on more of a local search (ie which 8's can be made with the new counting rules). It certainly alters the puzzle, but not in a way I immediately see more fun after mastering the craft. I'm now considering changes including min/max values for the numbers, or giving "linked" circles that must total up to some number, but themselves are not otherwise fixed. Not sure when I'll release those ideas, but I do think I may try a Min/Max series at the start of the new year since a lot of puzzle types have some play with that concept.
Robert Hutchinsonertchin on December 19th, 2010 06:38 am (UTC)
As I finished the Shikaku, I thought I had broken it. Then I thought the puzzle was broken. It took me five minutes to figure out that one rectangle had N+1 white squares instead of N. Sigh. Easy fix, though, and it does not dim my love of these puzzles.