The Project Euler thread - Page 14

**Reincarnate** · 05-21-2014, 06:59 PM

using brute force = not very interesting

usually more fun to try for the faster approaches

**rushyrulz** · 05-21-2014, 07:09 PM

I'm sure there's a very elegant mathematical solution for all of these, but I'm just trying to get as far as I can :P

**stargroup100** · 05-21-2014, 07:19 PM

I did the first 30 (excluding 12) and even a couple of the 300+ ones before I figured out 12. I don't know why but that one was hard for me

**rushyrulz** · 05-21-2014, 07:34 PM

Probably since there are so many different things you need to account for in 12. Not only do you need a gigantic 500+ factor number, but it also needs to be a summation of n number which is tricky to check for.

**Guest15937** · 05-21-2014, 07:42 PM

My brute force of 12 took 15 seconds to run.

**beary605** · 05-21-2014, 07:52 PM

does project euler ever teach you algorithms, e.x. dynamic programming, breadth/depth first search

**Reincarnate** · 05-21-2014, 08:43 PM

Quote:

Originally Posted by beary605

does project euler ever teach you algorithms, e.x. dynamic programming, breadth/depth first search

absolutely

even more so once you start venturing into the harder stages (where the problems also become much more interesting)

DP, especially, is used quite often

**rushyrulz** · 05-21-2014, 08:18 PM

Project Euler doesn't directly 'teach' you anything.

**beary605** · 05-21-2014, 08:23 PM

Quote:

Originally Posted by rushyrulz

Project Euler doesn't directly 'teach' you anything.

rephrasing question then

does project euler ever REQUIRE you to know algorithms, e.x. dynamic programming, breadth/depth first search

**rushyrulz** · 05-21-2014, 08:32 PM

It's basically algorithm development, and if dynamic programming, breadth/depth first search is required for efficiency sake, then yes.

Also, rewrote my factorization algorithm and I solved 12 in 5 seconds :P

**Reincarnate** · 05-21-2014, 08:44 PM

For example, try your hand at any of these:

http://projecteuler.net/problem=161
http://projecteuler.net/problem=425
http://projecteuler.net/problem=442

**Reincarnate** · 05-21-2014, 08:49 PM

And of course, (some) of the big kahunas that will require both mathematical and programmatical sorcery:

http://projecteuler.net/problem=289
http://projecteuler.net/problem=328
http://projecteuler.net/problem=344
http://projecteuler.net/problem=361
http://projecteuler.net/problem=415

**rushyrulz** · 05-21-2014, 08:52 PM

you almost have to be too smart...

**beary605** · 05-21-2014, 08:57 PM

ohoho this will be fun, i should get back to project euler

**axith** · 05-21-2014, 09:13 PM

Project Euler makes me feel dumb. I do appreciate the math tidbits that I'm forced to look up though. I had no clue of Euler's Totient function and many number theory ideas before messing with the problems.

**stargroup100** · 05-21-2014, 08:57 PM

ohhhh the eulerian circle one looks cool

really tempted to try that one lol

**Reincarnate** · 05-21-2014, 09:06 PM

also, honorable mention for just being a really cool and interesting problem with an elegant solution:

http://projecteuler.net/problem=202

leonid · 05-21-2014, 09:32 PM

http://projecteuler.net/problem=144

I still need to solve this one

**AutotelicBrown** · 05-22-2014, 04:12 AM

Those problems are fun. I'll try 328 later.

**stargroup100** · 05-25-2014, 01:50 AM

The latest problem, 473, looks really fun. http://projecteuler.net/problem=473

Right after reading it, I feel like finding the phidigital representation of an integer is NP complexity class. However, given the nature of these problems and the limit they ask for, I'm guessing there's some brilliant trick here.

EDIT: PFFFFT the trick was so stupidly obvious im dumb

05-21-2014, 06:59 PM	#1
Reincarnate x'); DROP TABLE FFR;-- Join Date: Nov 2010 Posts: 6,332	Re: The Project Euler thread using brute force = not very interesting usually more fun to try for the faster approaches

05-21-2014, 07:09 PM	#2
rushyrulz Digital Dancing! Join Date: Feb 2006 Location: 80 billion club, NE Age: 31 Posts: 12,981	Re: The Project Euler thread I'm sure there's a very elegant mathematical solution for all of these, but I'm just trying to get as far as I can :P __________________

05-21-2014, 07:19 PM	#3
stargroup100 behanjc & me are <3'ers Join Date: Jul 2006 Posts: 2,051	Re: The Project Euler thread I did the first 30 (excluding 12) and even a couple of the 300+ ones before I figured out 12. I don't know why but that one was hard for me __________________ Rhythm Simulation Guide Comments, criticism, suggestions, contributions, etc. are all welcome. Piano Etude Demon Fire sheet music

05-21-2014, 07:34 PM	#4
rushyrulz Digital Dancing! Join Date: Feb 2006 Location: 80 billion club, NE Age: 31 Posts: 12,981	Re: The Project Euler thread Probably since there are so many different things you need to account for in 12. Not only do you need a gigantic 500+ factor number, but it also needs to be a summation of n number which is tricky to check for. __________________

05-21-2014, 07:42 PM	#5
Guest15937 One-handed elite Join Date: May 2008 Posts: 1,464	Re: The Project Euler thread My brute force of 12 took 15 seconds to run. __________________ The renegade has betrayed me.

05-21-2014, 07:52 PM	#6
beary605 FFR Veteran Join Date: Oct 2008 Location: Canada Posts: 448	Re: The Project Euler thread does project euler ever teach you algorithms, e.x. dynamic programming, breadth/depth first search

05-21-2014, 08:18 PM	#8
rushyrulz Digital Dancing! Join Date: Feb 2006 Location: 80 billion club, NE Age: 31 Posts: 12,981	Re: The Project Euler thread Project Euler doesn't directly 'teach' you anything. __________________

05-21-2014, 08:32 PM	#10
rushyrulz Digital Dancing! Join Date: Feb 2006 Location: 80 billion club, NE Age: 31 Posts: 12,981	Re: The Project Euler thread It's basically algorithm development, and if dynamic programming, breadth/depth first search is required for efficiency sake, then yes. Also, rewrote my factorization algorithm and I solved 12 in 5 seconds :P __________________

05-21-2014, 08:44 PM	#11
Reincarnate x'); DROP TABLE FFR;-- Join Date: Nov 2010 Posts: 6,332	Re: The Project Euler thread For example, try your hand at any of these: http://projecteuler.net/problem=161 http://projecteuler.net/problem=425 http://projecteuler.net/problem=442 Last edited by Reincarnate; 05-21-2014 at 08:47 PM..

05-21-2014, 08:49 PM	#12
Reincarnate x'); DROP TABLE FFR;-- Join Date: Nov 2010 Posts: 6,332	Re: The Project Euler thread And of course, (some) of the big kahunas that will require both mathematical and programmatical sorcery: http://projecteuler.net/problem=289 http://projecteuler.net/problem=328 http://projecteuler.net/problem=344 http://projecteuler.net/problem=361 http://projecteuler.net/problem=415

05-21-2014, 08:52 PM	#13
rushyrulz Digital Dancing! Join Date: Feb 2006 Location: 80 billion club, NE Age: 31 Posts: 12,981	Re: The Project Euler thread you almost have to be too smart... __________________

05-21-2014, 08:57 PM	#14
beary605 FFR Veteran Join Date: Oct 2008 Location: Canada Posts: 448	Re: The Project Euler thread ohoho this will be fun, i should get back to project euler

05-21-2014, 09:13 PM	#15
axith FFR Veteran Join Date: Dec 2007 Posts: 1,249	Re: The Project Euler thread Project Euler makes me feel dumb. I do appreciate the math tidbits that I'm forced to look up though. I had no clue of Euler's Totient function and many number theory ideas before messing with the problems.

05-21-2014, 08:57 PM	#16
stargroup100 behanjc & me are <3'ers Join Date: Jul 2006 Posts: 2,051	Re: The Project Euler thread ohhhh the eulerian circle one looks cool really tempted to try that one lol __________________ Rhythm Simulation Guide Comments, criticism, suggestions, contributions, etc. are all welcome. Piano Etude Demon Fire sheet music

05-21-2014, 09:06 PM	#17
Reincarnate x'); DROP TABLE FFR;-- Join Date: Nov 2010 Posts: 6,332	Re: The Project Euler thread also, honorable mention for just being a really cool and interesting problem with an elegant solution: http://projecteuler.net/problem=202

05-21-2014, 09:32 PM	#18
leonid I am leonid Join Date: Oct 2008 Location: MOUNTAIN VIEW Age: 35 Posts: 8,080	Re: The Project Euler thread http://projecteuler.net/problem=144 I still need to solve this one __________________ Proud member of Team No

05-22-2014, 04:12 AM	#19
AutotelicBrown Under the scarlet moon Join Date: Jan 2014 Age: 31 Posts: 921	Re: The Project Euler thread Those problems are fun. I'll try 328 later.

05-25-2014, 01:50 AM	#20
stargroup100 behanjc & me are <3'ers Join Date: Jul 2006 Posts: 2,051	Re: The Project Euler thread The latest problem, 473, looks really fun. http://projecteuler.net/problem=473 Right after reading it, I feel like finding the phidigital representation of an integer is NP complexity class. However, given the nature of these problems and the limit they ask for, I'm guessing there's some brilliant trick here. EDIT: PFFFFT the trick was so stupidly obvious im dumb __________________ Rhythm Simulation Guide Comments, criticism, suggestions, contributions, etc. are all welcome. Piano Etude Demon Fire sheet music Last edited by stargroup100; 05-25-2014 at 02:28 AM..

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