Search found 113 matches

by v6ph1
Fri Jan 03, 2020 6:38 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 695
Replies: 2
Views: 306

Re: Problem 695

The Unit-Square is the black one.
For clarification the three points should be chosen that the rectangles combine to a clear non-square rectangle.
by v6ph1
Mon Oct 21, 2019 10:00 pm
Forum: News, Suggestions, and FAQ
Topic: Errors/Warnings/Bugs
Replies: 527
Views: 112442

Re: Errors/Warnings/Bugs

Thanks - for me, it's working again. :D
by v6ph1
Mon Oct 21, 2019 8:58 pm
Forum: News, Suggestions, and FAQ
Topic: Errors/Warnings/Bugs
Replies: 527
Views: 112442

Re: Errors/Warnings/Bugs

by v6ph1
Thu Aug 15, 2019 7:35 pm
Forum: Recreational
Topic: Mystery of Problem 480.
Replies: 2
Views: 777

Re: Mystery of Problem 480.

Statistics: There are ~5*10^17 possible words in it. And a lot of them are readable. Now calculate all of their Numbers. Build sums of three of them: You should find a sum which appears multiple times. (see Goldbach's conjecture) It is guaranteed if there are at least 1.5*10^6 readable words. And th...
by v6ph1
Sun Jun 30, 2019 8:28 pm
Forum: Number Theory
Topic: Generate tuples of pairwise coprimes with limit on largest element
Replies: 2
Views: 1584

Re: Generate tuples of pairwise coprimes with limit on largest element

You may work with a check-list for the primes:
1. Generate a list of all primes up to the limit
2. generate the first number by selecting primes (and powers) and cancel them out
3. go on for the 2nd, 3rd, ... number.
by v6ph1
Mon May 20, 2019 9:34 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 662
Replies: 6
Views: 3607

Re: Problem 662

For a smaller example 2x2: You can go: 0,0 - 0,1 - 0,2 - 1,2 - 2,2 0,0 - 0,1 - 1,1 - 2,1 - 2,2 0,0 - 0,1 - 1,1 - 1,2 - 2,2 0,0 - 1,0 - 1,1 - 2,1 - 2,2 0,0 - 1,0 - 1,1 - 1,2 - 2,2 0,0 - 1,0 - 2,0 - 2,1 - 2,2 --> 6 solutions only with step = 1 AND: (Two 1-steps and one 2-step) 0,0 - 0,1 - 0,2 - 2,2 0,...
by v6ph1
Sat Jan 12, 2019 12:06 am
Forum: Recreational
Topic: Some problem and user statistics
Replies: 5
Views: 5533

Re: Some problem and user statistics

What about the number of the best placements per person (ordered like in the olympic games)? 1. xyz (50 times 1st) 2. abc (26 times 1st) ... 19. dfg (40 times 2nd) ... Many of these statistics are interesting - but they are only as half as interesting, if you can not find your self in it. :wink: And...
by v6ph1
Wed Jan 02, 2019 11:28 pm
Forum: News, Suggestions, and FAQ
Topic: Code optimization techniques
Replies: 20
Views: 5081

Re: Code optimization techniques

I just changed your output so for each return, the current n is reported: -> the return is called twice as it's called by different function calls. For example fib(2) (the 4th call of fib) is startet, but it is still in progress until the result of fib(0) is returned. lookup[] = [-1, -1, -1, -1, -1,...
by v6ph1
Wed Jan 02, 2019 12:48 am
Forum: News, Suggestions, and FAQ
Topic: Code optimization techniques
Replies: 20
Views: 5081

Re: Code optimization techniques

It's only the return section of the previously called functions: The first calls of fib(5), fib(4), fib(3) and fib(2) did not immediately return - they need to call fib(n-1) and fib(n-2) first. So read it as follows: Stack: fib(5) (A.1) Call fib(5) -> nothing known; call fib(4) and fib(3) Stack: A T...
by v6ph1
Fri Dec 14, 2018 11:14 pm
Forum: Discrete Mathematics
Topic: Sorting...
Replies: 4
Views: 5936

Re: Sorting...

There is the problem of the handling of entries with equal values. So your "ArraySort" is not an algorithm for sorting, but for the mathematical union-sort operation. The algorithm of Array.sort() is not specified by the language it self: It can differ by the implementation - for primitive types, th...
by v6ph1
Wed Sep 12, 2018 5:10 am
Forum: News, Suggestions, and FAQ
Topic: New Language
Replies: 2
Views: 2790

Re: New Language

by v6ph1
Thu Aug 23, 2018 8:03 pm
Forum: Programming languages
Topic: which compiler to use for c++ programs
Replies: 2
Views: 4857

Re: which compiler to use for c++ programs

You should clarify it: Do you mean websites?

Most of us use an installed compiler:
gcc, visual studio c++, intel or llvm
by v6ph1
Tue Aug 21, 2018 9:20 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 113
Replies: 1
Views: 809

Re: Problem 113

Yes - bouncing is stated clearly as neither increasing nor decreasing.
by v6ph1
Sun Aug 19, 2018 9:32 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 039
Replies: 11
Views: 3260

Re: Problem 039

Right angle triangle should be clear enough. Only 1 angle of a degenerated triangle can be determined exactly: 0° between the two identical sides. The other two angles are undetermined. In any problem description, corner cases are named extra. (Integer 0, degenerated polygons,...) But this does not ...
by v6ph1
Thu Aug 09, 2018 11:25 pm
Forum: Number Theory
Topic: An Infinite Prime Number Generator
Replies: 5
Views: 6112

Re: An Infinite Prime Number Generator

For sure, mod 6 will have a better performance than mod 2 -> the speedup is around 1.4 ... 1.5 and for mod 30, we will have a speedup of 1.8 in comparison to mod 2. It is possible to optimize the performance of the higher versions as mod 6. But the max performance (n/2)/EulerPhi(n), which is only hi...
by v6ph1
Thu Aug 09, 2018 8:00 am
Forum: Number Theory
Topic: An Infinite Prime Number Generator
Replies: 5
Views: 6112

Re: An Infinite Prime Number Generator

I don't know how the checks will be compiled, but I think, there is a hidden complexity in the loop checking: e.g. res = k + step while res in D or res % 30 not in (1, 7, 11, 13, 17, 19, 23, 29): You iterate through all (uneven) multiples - even if you don't store them, but in the case mod 6, you on...
by v6ph1
Sun Aug 05, 2018 12:47 pm
Forum: News, Suggestions, and FAQ
Topic: Problem with progress badge?
Replies: 2
Views: 2416

Re: Problem with progress badge?

The graphic is not updated immediately after a problem is solved and sometimes, the browser cache stores an old version.
So: try to view the picture in 1 hour and reload it without cache (Ctrl + F5 in most browsers).
by v6ph1
Mon Jul 09, 2018 10:21 am
Forum: Number
Topic: an old maths olympiad question
Replies: 28
Views: 17152

Re: an old maths olympiad question

If n>3, there is no integer solution:

a = (n-2)/n * pi

1/1 = 1/(2-2cos(a)) + 1/(3-2cos(2a-pi))

-> n = 13.757
by v6ph1
Mon Jul 09, 2018 8:30 am
Forum: Number
Topic: an old maths olympiad question
Replies: 28
Views: 17152

Re: an old maths olympiad question

3-sided:
A1A2 = A1A3 = A2A3 = 1 = S
And if A4 didn't exist, A1A4 = infinity

-> 1/1 = 1/1 + 1/infinity ...
-> 1 = 1 + 0

The usage of capital letters is typical for Points, small letters are used for lengths.
by v6ph1
Tue May 29, 2018 5:56 am
Forum: Clarifications on Project Euler Problems
Topic: Problem 396
Replies: 5
Views: 2046

Re: Problem 396

Read carefully:
It can also be verified that SumG(n) = 2517 for 1 <= n < 8.
The second one is just a less not a less-equal