Search found 75 matches

by PurpleBlu3s
Fri Jan 01, 2021 1:06 am
Forum: Clarifications on Project Euler Problems
Topic: Problem 740
Replies: 7
Views: 1206

Re: Problem 740

I agree the problem is ambiguously worded. My initial interpretation was the 123123 version, but I see the 112233 version fits better given this statement: The process will fail if the last person gets at least one slip with their own name. Perhaps something like this would be clearer? As before eac...
by PurpleBlu3s
Thu Dec 31, 2020 6:15 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 684
Replies: 16
Views: 7831

Re: Problem 684

Generalise the problem such that F(N) = S(f 2 ) + ... + S(f N ). I have a (slow) brute force algorithm, a medium algorithm and a fast algorithm. They all agree as far as I can push the slower ones, which is up to F(22) for the brute force and F(46) for the medium algorithm. The brute force and mediu...
by PurpleBlu3s
Thu Oct 04, 2018 4:19 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 444
Replies: 6
Views: 4698

Re: Problem 444

Thanks for the clarification.
by PurpleBlu3s
Tue Oct 02, 2018 1:53 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 444
Replies: 6
Views: 4698

Re: Problem 444

I would like to clarify the meaning of option two: "The player can trade his unscratched ticket for a previous player's scratched ticket..." Does this mean that the current player can trade their ticket for ANY previous player's ticket (e.g. player p can trade with any player who hasn't le...
by PurpleBlu3s
Wed Jun 01, 2016 12:25 pm
Forum: Combinatorics
Topic: Partitions with a unique maximum part
Replies: 4
Views: 9264

Re: Partitions with a unique maximum part

If you think of partitioning data based on value, then what I mean is the number of occurrences of the mode. For example, we have a set of 8 data points: 1 1 2 3 2 2 2 4 Grouping them based on their value: (2 2 2 2) (1 1) (3) (4) Counting the size of the groups: 4 2 1 1 This is a partition of 8, and...
by PurpleBlu3s
Tue May 31, 2016 5:00 pm
Forum: Combinatorics
Topic: Partitions with a unique maximum part
Replies: 4
Views: 9264

Partitions with a unique maximum part

I am in need of a way to calculate a few things about partitions. If we say there are 4 objects (n=4), then the partitions of 4 are: 4 3 + 1 2 + 2 * 2 + 1 + 1 1 + 1 + 1 + 1 * * these partitions do not have a unique mode. I'm looking for a function, p'(n), that will tell me how many partitions there ...
by PurpleBlu3s
Wed Jul 25, 2012 2:25 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 121
Replies: 34
Views: 17146

Re: Problem 121

For 10 turns, can anyone confirm 124829/39916800 is the probability of winning That's odd. My program got the correct answer for 4 and 15 turns, but it says that 177299/39916800 is the probability of winning in 10 turns. Sure you didn't leave out an event? (Of course, with the rounding caused by th...
by PurpleBlu3s
Wed Jul 18, 2012 3:41 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 188
Replies: 4
Views: 3437

Re: Problem 188

I just posted a question in the forum for this problem - I would appreciate any replies.
by PurpleBlu3s
Thu Jun 28, 2012 2:50 pm
Forum: Number
Topic: A good number theory book?
Replies: 5
Views: 15763

Re: A good number theory book?

Thanks for your posts. I've decided to get Hardy and Wright's book for now.
by PurpleBlu3s
Thu Jun 28, 2012 2:49 pm
Forum: Programming languages
Topic: Weird issue with C
Replies: 11
Views: 10245

Weird issue with C

I don't if anyone has ever seen anything like this before, but basically, I was doing one of the problems in C, with an array of primes, primes[0] = 2, primes[1] = 3, primes[2] = 5, ... After I initially set up the array, I confirmed that primes[1] == 3, however, inside a function, called later, pri...
by PurpleBlu3s
Sat Jun 23, 2012 3:20 pm
Forum: Number
Topic: A good number theory book?
Replies: 5
Views: 15763

A good number theory book?

Hi, I was wondering if anyone could recommend a good book on number theory that goes into a decent amount of depth? Preferably aimed at people with A-level maths plus a bit of undergraduate discrete maths or something like that. I would prefer that the book covers as many big areas as possible, thou...
by PurpleBlu3s
Fri Jun 22, 2012 1:44 pm
Forum: Applied Mathematics
Topic: Probability related problems
Replies: 3
Views: 11120

Re: Probability related problems

Thanks. I did not realise what expected value actually meant (especially when written "expected number of ...").

Making it work with conditional probabilities seems tricky though - for the problem I'm trying, I'm getting rather nonsensical answers. :<
by PurpleBlu3s
Fri Jun 22, 2012 1:25 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 371
Replies: 42
Views: 24614

Re: Problem 371

Can anyone confirm the probability of not having a win after seeing 10 plates is 0.95586930 (8 s.f.)?
by PurpleBlu3s
Thu Jun 21, 2012 11:44 pm
Forum: Applied Mathematics
Topic: Probability related problems
Replies: 3
Views: 11120

Probability related problems

I'm rather stumped with the PE problems about probability where it says something like "give your answer to 8 decimal places", and is looking for a quantity that can only be an integer in any one instance. I just have no idea what to look at - in all my attempts and with all my (limited) k...
by PurpleBlu3s
Thu Jun 21, 2012 7:04 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 371
Replies: 42
Views: 24614

Re: Problem 371

I have only been able to get a formula that works with integers - and it doesn't extend to reals. Is it possible to come up with a formula to work with reals or does one need to find the two integers the answer lies between and do something else from there?
by PurpleBlu3s
Sun Jun 17, 2012 1:07 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 158
Replies: 11
Views: 6828

Re: Problem 158

So I've returned to this problem after a while, and I wanted to check if anyone could confirm my value for n=4, 164450?

Thanks.
by PurpleBlu3s
Sun May 20, 2012 9:42 am
Forum: Applied Mathematics
Topic: Physics Problem
Replies: 4
Views: 10687

Re: Physics Problem

If you neglect friction, they end up going the same speed, but the one that went into the trough will be ahead because it was going faster for a time. If the question was "Which will reach the finish line first?", that's the answer. If the question was "Which will have the higher spe...
by PurpleBlu3s
Sun May 20, 2012 12:03 am
Forum: Applied Mathematics
Topic: Physics Problem
Replies: 4
Views: 10687

Re: Physics Problem

One argument is that air resistance will increase non-linearly with speed, so the ball going through the trough might be expected to be faster and meet with more air resistance, and come out slower. However, this is likely to be a negligible effect so probably the proper answer is something else? I...
by PurpleBlu3s
Sat May 19, 2012 4:51 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 103
Replies: 38
Views: 16572

Re: Problem 103

Thank you. I was going mad thinking my algorithm was wrong when I was so sure it was correct - I had a silly problem with an array operation!
by PurpleBlu3s
Sat May 19, 2012 4:05 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 103
Replies: 38
Views: 16572

Re: Problem 103

Can someone point out what the pair of disjoint subsets is that invalidates this as a solution for n=6?

A = {11,16,19,21,22,23}, S(A) = 112

I cannot anything wrong with it, though obviously there must be (at least) one pairing.

Thanks.