Cephalogenic

or, stuff that I dragged out of my head

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Location: Moncton, New Brunswick, Canada

Sunday, November 23, 2008

Eyeballing

This doesn't really have anything to do with words, exactly, but there is a point to it.

Project Euler is a large(ish) collection of math problems, ranging from sort of difficult to insane. Jim (who has a math degree) and I (who do not) like this sort of thing, so we spent a good deal of this evening clawing through them. I solved four or five of them using a spreadsheet, as did Jim, although he's finished more than I have (because he can program in Python to do the nasty prime-number problems and such).

Now, here's why I mention this to you: problem 8. It reads as follows:

Find the greatest product of five consecutive digits in the 1000-digit number.

73167176531330624919225119674426574742355349194934
96983520312774506326239578318016984801869478851843
85861560789112949495459501737958331952853208805511
12540698747158523863050715693290963295227443043557
66896648950445244523161731856403098711121722383113
62229893423380308135336276614282806444486645238749
30358907296290491560440772390713810515859307960866
70172427121883998797908792274921901699720888093776
65727333001053367881220235421809751254540594752243
52584907711670556013604839586446706324415722155397
53697817977846174064955149290862569321978468622482
83972241375657056057490261407972968652414535100474
82166370484403199890008895243450658541227588666881
16427171479924442928230863465674813919123162824586
17866458359124566529476545682848912883142607690042
24219022671055626321111109370544217506941658960408
07198403850962455444362981230987879927244284909188
84580156166097919133875499200524063689912560717606
05886116467109405077541002256983155200055935729725
71636269561882670428252483600823257530420752963450


and that's not a math problem, it's a proofreader's problem, and therefore of (theoretical) interest to me and any readers. I looked over the array of numbers and almost instantly zeroed in on the appropriate area. I was briefly misled, and got the wrong answer, but another quick skim led me to the correct set of digits (just a couple of places over from where I had originally settled) and the correct answer.

So you should give the problem a try. Seriously. It has hardly anything to do with math, except for the last bit where you multiply the five digits together. Otherwise, it's a pretty good test of a copy-editor's skills, I think.

2 Comments:

Anonymous OmegaMom said...

I may be way off, but 40824? I just looked for the spot with the most 9s in it, then with the highest numbers aside from 9s...?

Sunday, November 23, 2008 9:39:00 PM  
Blogger pyramus said...

That's it. Eighth row down, fifteenth through nineteenth digits. I was thrown off by the twentieth and twenty-first digits and chose those instead of the fifteenth and sixteenth, but soon discovered my mistake.

As I said, a proofreader's puzzle, a mere exercise in pattern-matching. I'm not sure what it's doing in a collection of (mostly challenging) mathematics problems.

Monday, November 24, 2008 2:04:00 AM  

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