Comments on: Google treasure hunt: last puzzle

By: Treasure hunt clues

Treasure hunt clues — Mon, 03 May 2010 19:19:47 +0000

It would be great if Google ran another treasure hunt… it did sound like a lot of fun.

By: Ya, I Am A Dastard

Ya, I Am A Dastard — Tue, 24 Jun 2008 08:57:33 +0000

when brute works, nothing can be better

By: Puzzle puzzle every where : Burad’s Blog

Puzzle puzzle every where : Burad’s Blog — Sat, 07 Jun 2008 19:33:18 +0000

[...] « Google treasure hunt: last puzzle [...]

By: Abhishek Ojha

Abhishek Ojha — Thu, 05 Jun 2008 07:00:28 +0000

good Luck !

By: Bryce

Bryce — Thu, 05 Jun 2008 05:09:54 +0000

This one was pretty fun. I couldn’t find a good mathematical approach (Problems related to sums of primes seem to be hard. See the Goldbach conjecture), so I wrote a Haskell program that used a tower of lazy immutable Arrays, each built by referencing an arrays of shorter consecutive prime sums. I then marched linearly through the array for the longest consecutive sum, until I found a prime and then used a binary search to check if that number was found in each of the other arrays. Since each of the arrays can be defined in terms of each other, this solution represents a sort of dynamic programming solution, and since Haskell is lazy the binary search doesn’t have to compute the entire array that we’re performing binary search on. It still took about 9 seconds to find the answer on my laptop though. I’m interested to see more elegant solutions.