## USPC Practice Set

The 2012 USPC instructions were released several hours ago. I’ve pointed out some past examples of types in a comment on motris’s post here. But this post is really for my constructions of two of the types for which I have not found good examples.

The first one is perhaps only worth 20 if you insist on doing it logically. I’m guessing the second one would be 25, so it overshoots a bit.

16. Space Probes
Locate two probes in each row and each column so that they don’t touch each other, not even diagonally. Each clue outside the grid is the number of empty squares between the two probes in the corresponding row or column.

USPC 2012: #16 practice

Answer Entry: Enter the number of empty squares between each clue and the first probe in the corresponding row or column, starting with the clues across the top from left to right, then the clues along the left, from top to bottom.
Highlight for answer: [ 2,0,1 ]

18. Magic Order
Enter the digits 1 through 6 once in each row and column so that 24 distinct 6-digit numbers are formed horizontally and verticallyâ€”reading forward and backward. Each clue pointing to a number indicates the position of that number when all 24 6-digit numbers are ordered from smallest to largest.

USPC 2012: #18 Practice

Answer Entry: Enter the digits in the 3rd row followed by the digits in the 5th row.
Highlight for answer: [ 154362, 245136 ]

Another example of #18 was posted by thedan here, which I found after putting up this post.

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### 8 Responses to “USPC Practice Set”

1. Thomas Snyder Says:

about 5 minutes on both. (maybe that’s just today’s story). Anyway, I had the answer entry on your space probes long before I had the finished grid up there, having done the bifurcation backwards. The Magic Order was very nice.

• MellowMelon Says:

It was my impression after just reading the instructions that Space Probes is going to be very easy to shortcut using the answer entry regardless. I suppose the puzzle above exacerbates the problem a little though.

2. Elolo Gargounsky Says:

That Magic order was really good! but I felt the space probes was a little guess-and-checky. I might have overlooked some elegant way to do it.

• MellowMelon Says:

As a star battle kind of puzzle it is definitely understandable to attack it with guessing. However I did make this one to have a logical solution, since otherwise it wouldn’t be any better than the ones on Friedman’s site. It’s just tricky to find.

Here’s the idea:
1. The 5s should allow you to get lots of Xs on C1-2 and R4-6, and I’m not just referring to their intersection.
2. The 1 can get you some more Xs in R1 and R2.
3. R2 having little space gets you some Xs. Then C6 and C8 have little space. Then R8 has little space.
4. You can figure out the general area of the four probes in C6-7 and C7-8. This analysis gives you a contradiction if R6C7 is not shaded. After that you’re basically home.

3. Dan Katz Says:

Yours is much nicer than mine. My compliments to the chef.

4. ksun48 Says:

I liked the space probes one, although I spent 45 seconds before realizing R7C2 gave an X on R8C3 .

5. betaveros Says:

Could somebody give me a nudge on the Magic Order? I’ve stared at it forever and I’ve slept on it, and all I have are the six easy border cells…