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 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

 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.

 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

 stargroup100 05-25-2014 03:40 PM

This problem is still hard as balls though. The "obvious" algorithm doesn't really help you compute anything efficiently, at least not without some heavy-duty work put onto it.

 rushyrulz 05-28-2014 08:29 PM

Code:

```Problem 17 If the numbers 1 to 5 are written out in words: one, two, three, four, five, then there are 3 + 3 + 5 + 4 + 4 = 19 letters used in total. If all the numbers from 1 to 1000 (one thousand) inclusive were written out in words, how many letters would be used? NOTE: Do not count spaces or hyphens. For example, 342 (three hundred and forty-two) contains 23 letters and 115 (one hundred and fifteen) contains 20 letters. The use of "and" when writing out numbers is in compliance with British usage.```

this one was a recursive nightmare, almost wanted to pencil and paper it.

 stargroup100 05-29-2014 02:37 AM

Quote:
 Originally Posted by rushyrulz (Post 4142267) Code: ```Problem 17 If the numbers 1 to 5 are written out in words: one, two, three, four, five, then there are 3 + 3 + 5 + 4 + 4 = 19 letters used in total. If all the numbers from 1 to 1000 (one thousand) inclusive were written out in words, how many letters would be used? NOTE: Do not count spaces or hyphens. For example, 342 (three hundred and forty-two) contains 23 letters and 115 (one hundred and fifteen) contains 20 letters. The use of "and" when writing out numbers is in compliance with British usage.``` this one was a recursive nightmare, almost wanted to pencil and paper it.
fyi a pencil and paper solution could take less than 10 min LOL

 leonid 06-1-2014 01:16 AM

That was easier than I feared, but it still took me a couple hours to come up with the right code

 leonid 06-1-2014 04:32 AM

PARI/GP rocks

 leonid 06-1-2014 05:15 AM

I'm on fire

 stargroup100 06-1-2014 06:32 AM

Quote:
 Originally Posted by leonid (Post 4143880) PARI/GP rocks
that thing is fucking amazing

I put it on my phone LOL

 leonid 06-1-2014 06:52 AM

Used Ruby this time

 rushyrulz 06-1-2014 04:54 PM

Quote:
 Originally Posted by stargroup100 (Post 4142360) fyi a pencil and paper solution could take less than 10 min LOL
I'm aware, but I am not doing this because I want fast solutions, I'm doing this to strengthen my programming skills.

Just like how problem 19 (how many Sundays occurred on the first day of the month in the 20th century?) could be easily guessed by
, but I wrote a program for it anyway.

 Reincarnate 06-1-2014 05:16 PM

The first 100 problems are pretty simple

Try some later problems for more of a challenge

 rushyrulz 06-1-2014 05:50 PM

I'm having a hoot with the first 100 for now D:

 igotrhythm 06-1-2014 08:54 PM

90% of these have me saying "I wish I knew how to solve this problem period, let alone write a program to solve it."

 leonid 06-1-2014 09:23 PM

Dynamic programming

 leonid 06-1-2014 10:41 PM

Another DP
Ruby is slow..

 leonid 06-2-2014 12:27 AM