Search found 84 matches

by TheEvil
Tue Dec 17, 2013 6:44 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 011
Replies: 66
Views: 9317

Re: Problem 011

If you do that, you will definitely get the green tick.
by TheEvil
Tue Dec 03, 2013 8:52 pm
Forum: News, Suggestions, and FAQ
Topic: Errors/Warnings/Bugs
Replies: 539
Views: 129130

Re: Errors/Warnings/Bugs

wonderful ;-)
by TheEvil
Tue Dec 03, 2013 8:26 am
Forum: News, Suggestions, and FAQ
Topic: Errors/Warnings/Bugs
Replies: 539
Views: 129130

Re: Errors/Warnings/Bugs

Hello.
It's not a bug, but I use PE with lights turned off. The new Last 10 problems solved section on Progress page is a little invisible. Anyway it is a great idea and I love it.
Greetings,
TheEvil
by TheEvil
Thu Nov 28, 2013 7:00 am
Forum: Number
Topic: Mathematics
Replies: 3
Views: 2526

Re: Mathematics

First of all, it is not an equation. But if you are intrested in the closed form of that series:

x*n - n*(n-1)*y/2
by TheEvil
Thu Nov 28, 2013 6:53 am
Forum: Number Theory
Topic: Sublattices in Z^2
Replies: 5
Views: 2911

Re: Sublattices in Z^2

Exercise 4 and 5 are exactly the same. x=y (mod 3) /multiply by 2 --- Exercise 5 2x=2y (mod 3) --- Exercise 4 If you like the coset language, then let the set given in Exercise 5 be A. The nine cosets in Z 2 : A (1,0)A (2,0)A (0,1)A (1,1)A (2,1)A (0,2)A (1,2)A (2,2)A That's why you get 9, as the ind...
by TheEvil
Tue Nov 26, 2013 6:59 pm
Forum: Number Theory
Topic: Sublattices in Z^2
Replies: 5
Views: 2911

Re: Sublattices in Z^2

When I hear the word lattice, I always think of the algebraic structure, with meet and join operation. You can read about them in wikipedia, and a lot of other books, maybe in general introductions to algebra.
Wikipedia link:
http://en.wikipedia.org/wiki/Lattice_%28order%29
by TheEvil
Tue Nov 26, 2013 6:44 am
Forum: Number Theory
Topic: Sublattices in Z^2
Replies: 5
Views: 2911

Re: Sublattices in Z^2

1. not sublattice, since (1,0)+(0,1) is not belong to the set the others are sublattices with indeces: 2. infinity 3. two 4. nine 5. nine, this is the same sublattice as in example 3 I'm nor sure totally, since your definition of sublattice seems a little wierd to me. Any definition, which does not ...
by TheEvil
Thu Nov 21, 2013 4:04 pm
Forum: Number Theory
Topic: Mathematicians Team Up To Close the Prime Gap
Replies: 2
Views: 2257

Re: Mathematicians Team Up To Close the Prime Gap

You misread a quantor. Not all prime neighbours have distance less than 70 million, but there exists infinetely many prime numbers, for which the distance between them is less than 70 million. Zhang's result is incredibly amazing, since no one was ever this close to the twin primes conjecture. You h...
by TheEvil
Wed Nov 20, 2013 5:50 am
Forum: Number
Topic: Primitive root
Replies: 1
Views: 2710

Re: Primitive root

I don't know how much do you know about field theory, but the most simple way to prove it, is to use field theory. Every Z p is a finite field. If you leave 0 out, and take only the multiplication, you get a cyclic group of order p-1. It is not trivial, but from this it is easy to prove. Z p x (the ...
by TheEvil
Sat Nov 16, 2013 9:23 am
Forum: News, Suggestions, and FAQ
Topic: Level 17?
Replies: 5
Views: 2011

Re: Level 17?

I don't think you can do that. But you can add this to your signature:
http://projecteuler.net/profile/ving.png

Image
by TheEvil
Thu Nov 14, 2013 7:25 am
Forum: Clarifications on Project Euler Problems
Topic: Problem 359
Replies: 13
Views: 4579

Re: Problem 359

You should always check everyone wit the last occupied room on every floor. For Person 4, you should check 4+3=7 instead of 4+1=5. Then do it for floow 2, and so on.
by TheEvil
Wed Nov 06, 2013 6:36 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 027
Replies: 25
Views: 7415

Re: Problem 027

If you feed positive numbers in the polynom n2+an+b, it is the same as feeding negative numbers in n2-an+b. So the problem won't be easier and the only change would be in the sign of the answer. Anyway you will get the correct answer for increasing numbers.
by TheEvil
Sun Oct 20, 2013 7:20 pm
Forum: Combinatorics
Topic: Simple Antichain Question
Replies: 1
Views: 2084

Re: Simple Antichain Question

I'm supposing that P(n) is the power set of an n element set in this comment. I don't think that this queation is simple. The upper bound for an antichain is reached at [n/2], and called Sperner theorem. See at the end of this:http://mathworld.wolfram.com/Antichain.html I have seen the proof of this...
by TheEvil
Sun Sep 29, 2013 9:33 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 142
Replies: 16
Views: 6509

Re: Problem 142

The correct answer is lower than yours. It has the same number of digits as yours.
By the way: you can check any of your answers easily with a calculator, the hard part is to find the smallest one.
by TheEvil
Wed Sep 18, 2013 4:15 pm
Forum: Programming languages
Topic: in C: Optimal way to measure elapsed time?
Replies: 2
Views: 7930

Re: in C: Optimal way to measure elapsed time?

I've stolen this from someone from a post thread. It's basically the same, but you can control when to start the timer. #include <time.h> clock_t start; //declaration of time type variable int main(){ start=clock(); /* Your program goes here*/ printf("Time: %f sec",(double)(clock()-start)/CLOCKS_PER...
by TheEvil
Thu Jul 25, 2013 6:11 am
Forum: Clarifications on Project Euler Problems
Topic: Problem 003
Replies: 128
Views: 43728

Re: Problem 003

If you do it properly, you have to know only that 3 is the smallest odd prime number. You don't have to know any other prime numbers. Maybe it doesn't help you, but it's the key idea.
by TheEvil
Tue Jul 23, 2013 7:52 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 003
Replies: 128
Views: 43728

Re: Problem 003

When I did it I used 32 bit integers. It was a lot more complicated than with 64 bit integers. That is trivial if you have the necessary idea.
by TheEvil
Tue Jul 23, 2013 6:08 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 003
Replies: 128
Views: 43728

Re: Problem 003

Since you are looking for prime factors, why don't you try to factorize it, instead of checking every prime number. I think this hint should be enough.
by TheEvil
Thu Jul 11, 2013 6:56 am
Forum: Clarifications on Project Euler Problems
Topic: Problem 143
Replies: 26
Views: 9968

Re: Problem 143

@karluk
Sorry I didn't see that, I thought the your problem was with X and T. Sorry again.
by TheEvil
Wed Jul 10, 2013 4:11 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 143
Replies: 26
Views: 9968

Re: Problem 143

There appears to be a minor discrepancy between the statement of problem 143 and the accompanying diagram. The statement of the problem says XB = q, and XC = r for any point X in triangle ABC. But the diagram labels TC = q and TB = r for the Torricelli point. In order to be consistent with the stat...