Boy is it a relief to hear how tough everyone found the Mutant Number Skeleton. It took me about twice as long to do as any other puzzle in the set during my testsolve, and I had to do trial and error. When I was told of the intended solution I figured I had just royally messed up, but it looks like I'm not the only one.

I commented to motris that experience solving nikoli puzzles, especially those that they publish online, would confer a substantial advantage for this test. Not surprising to see H.Jo win, with that in mind.

It was certainly the outlier in your times, but was actually one of Wei-Hwa's faster solves (under two minutes, in line with the Hard of the same type). I figured it was the most high variance of the mutants, since the solve is so dependent on noticing a property of the number list and does not solve in any other way like brute force which can be applied on a lot of the other puzzles.

The key insight to the Number Skeleton mutant is to see that all the 6 digit numbers have digits strictly increasing from left-to-right. This means as you follow a path of five-cell entries from top-left to bottom-right, the digits along that entire path must also be strictly increasing, but this places a lot of constraints on the digits at the intersections, particularly the first digit of the entry going down the rightmost column. Along this thinking you should be able to get that the intersecting 3 cell entries are 131 and 615 and from those get the other 3 cell entries which will help complete the puzzle.

Edited by motris 2010-10-19 4:00 AM

6 Germans in top 10.
What do you have to say about that with WPC round the corner? ;-)

At the WPC, there cannot be more than 4 in the top 10

Also, 3 of the four USA participants were involved in creating / testing the puzzles.

alternatively, you can simply go back to the original plan and award the maximum bonus only in the case of 10/10 puzzle solved. This also considering how kind you have been in forgiving typing mistakes, this reduces the impact of wrong transcriptions.
stefano