## Ressources and courses for solving project euler problems

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Creepy_P0ney
Posts: 2
Joined: Tue Mar 25, 2014 5:19 pm

### Ressources and courses for solving project euler problems

Hey guys, I love solving problems like those we can find on project euler, i can program, that's not a problem, the problem i have is the mathematical background needed, so i would like to know if some of you have some links or tips and tricks to give me.

Thanks

(sorry for my english, i'm french)

Svartskägg
Posts: 55
Joined: Thu Mar 29, 2012 12:55 pm
Location: Sweden

### Re: Ressources and courses for solving project euler problem

I don't think you need much specific knowledge about math. What you need in most problems is just doing simple algebraic manipulations on paper. It helps to know some basic concepts of number theory, such as: prime number.

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Creepy_P0ney
Posts: 2
Joined: Tue Mar 25, 2014 5:19 pm

### Re: Ressources and courses for solving project euler problem

Ok, thanks, I'll search for number theory course :p
But I have a last question, how do i store very big numbers in memory such as 100! or the terms of fibonacci sequence when u(n) grows (and it grows really fast). For big numbers (but not as big as 100!) I use the type __int64 (in C)

thundre
Posts: 356
Joined: Sun Mar 27, 2011 10:01 am

### Re: Ressources and courses for solving project euler problem

Creepy_P0ney wrote:Ok, thanks, I'll search for number theory course :p
But I have a last question, how do i store very big numbers in memory such as 100! or the terms of fibonacci sequence when u(n) grows (and it grows really fast). For big numbers (but not as big as 100!) I use the type __int64 (in C)
There are "big integer" or "arbitrary precision" libraries which can handle very large numbers. But very few PE problems actually require that.

A knowledge of modular arithmetic is useful. If they ask for the last 9 digits of A*B, you only need to know the last 9 digits of A and the last 9 of B and multiply those together, then take the last 9 of that. http://en.wikipedia.org/wiki/Modular_arithmetic

vamsikal3
Posts: 113
Joined: Sat Oct 01, 2016 9:25 am

### Re: Ressources and courses for solving project euler problems

I started solving PE problems about 2 and 1/2 years ago. I am also a programmer, not a mathematician, so I could with my current math skills solve about 365 problems. I feel like I have max'd out and any left over problems are beyond my current skill. So I started looking for ways to improve my skill-set to help solve more PE problems. I have hit upon the following two resources which are available at LibGen as PDFs.

1. Elementary Number Theory, 7th edition by David M Burton: https://www.amazon.com/Elementary-Numbe ... 073383147/

2. Elementary Number Theory, 6th Edition by Kenneth H Rosen: https://www.amazon.com/Elementary-Numbe ... 321500318/

Burton's book is more easy, Rosen's book might be more accessible if you have worked through Burton's book first. A lot of theory behind PE problems shows up in these books, a sample being: figurate numbers, greatest common divisor, totients, continued fractions, primitive roots, linear diophantine equations, sum of squares. In fact I was able to solve PE 273 after I read the chapter 13 of Burton's book. I wish I had access to these books 2 and a 1/2 years ago, when I was starting out on PE. Hopefully these books will help PE newbies improve their math skills.
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