Search found 51 matches

by wrongrook
Wed Nov 08, 2017 7:40 pm
Forum: Discrete Mathematics
Topic: Finding shortest subarray with given value: many queries
Replies: 2
Views: 5301

Finding shortest subarray with given value: many queries

Background I came across this interesting stack overflow question: https://stackoverflow.com/questions/47111546/finding-smallest-subarray-lengths-for-given-multiple-queries#comment81192683_47111546 Question There is an array n = 1 million in length containing positive integers. There are also n = 1...
by wrongrook
Sun Feb 21, 2016 1:12 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 548
Replies: 5
Views: 2326

Problem 548

Can you also give the value for g(1)?

I am not sure from the problem statement whether g(1) should be 0 or 1?
by wrongrook
Tue Apr 28, 2015 9:40 pm
Forum: News, Suggestions, and FAQ
Topic: Errors/Warnings/Bugs
Replies: 525
Views: 105818

Re: Errors/Warnings/Bugs

I've just enjoyed solving problem 459 (after a year and a bit) but noticed a slightly curious thing when looking to see how quickly others had managed to solve it: The fastest solvers list for Problem 459 only mentions 61 people, while the archives page lists 114 people as having solved it. Is this ...
by wrongrook
Tue Aug 26, 2014 6:20 pm
Forum: Game Theory
Topic: Optimal strategy for a game on a binary tree
Replies: 0
Views: 6515

Optimal strategy for a game on a binary tree

I have been struggling to solve a problem from CodeForces involving the optimal strategy for a two player game played on a tree. (This is a problem from a finished contest - but no editorial has been published yet as far as I can see.) I have put a description of the problem on Stack Overflow http:/...
by wrongrook
Tue Mar 04, 2014 7:37 pm
Forum: News, Suggestions, and FAQ
Topic: Where's my badge? :)
Replies: 12
Views: 3822

Re: Where's my badge? :)

Incidentally, I notice that I have now lost my perfection badge :(

I guess the system spotted I have been getting lazy recently and not attempting many problems...
by wrongrook
Sat Dec 28, 2013 1:59 pm
Forum: News, Suggestions, and FAQ
Topic: Credits for Authors of problems
Replies: 7
Views: 2956

Credits for Authors of problems

I was just wondering whether it would be good to note somewhere who suggested each problem? It might show a bit of appreciation to those able to come up with the problems, and solvers might be able to start recognising the names of problem setters whose questions they enjoy, perhaps helping them whe...
by wrongrook
Sun Jan 13, 2013 7:50 pm
Forum: News, Suggestions, and FAQ
Topic: Posting solutions outside of Project Euler's site
Replies: 25
Views: 12473

Re: Posting solutions outside of Project Euler's site

For what it's worth, I would prefer there not be such limits before people can solve recent problems. If I recommend Project Euler to someone who wants to learn a new language then I suggest starting from the easiest problems, but if someone just wants to have fun and play with solving some mathemat...
by wrongrook
Sun Sep 16, 2012 5:09 pm
Forum: Clarifications on Project Euler Problems
Topic: problem 394
Replies: 7
Views: 2545

Re: problem 394

I wonder if you are thinking about the problem like a game where Jeff is choosing where to make the cuts? In this case you are correct, and Jeff can "win" the game on his first move by cutting off most of the cake. However, this is not the intention of the problem. It is better to think of it as a s...
by wrongrook
Mon Jun 11, 2012 9:00 am
Forum: Recreational
Topic: Have you written a program to write a program?
Replies: 7
Views: 4567

Re: Have you written a program to write a program?

I use this kind of metaprogramming quite often when I need to write in hardware description languages (such as Verilog or VHDL) because these languages are relatively verbose. However, my preferred direction is opposite to yours - I tend to write Python code to generate the RTL output. I find my met...
by wrongrook
Sat May 19, 2012 8:10 pm
Forum: Applied Mathematics
Topic: Physics Problem
Replies: 4
Views: 7920

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?
by wrongrook
Sun May 13, 2012 7:54 pm
Forum: News, Suggestions, and FAQ
Topic: how to add the solution
Replies: 1
Views: 2662

Re: how to add the solution

Welcome! In Project Euler you just need to submit the numerical answer not the code. Type the answer you found in the box labelled Answer. Type the 5 digit number shown in the image in the box labelled Confirmation Code. Press the Check button. You will then get a green tick (if the answer is right)...
by wrongrook
Wed Mar 28, 2012 1:46 pm
Forum: Resources
Topic: Resources for Programming Competitions?
Replies: 4
Views: 9304

Re: Resources for Programming Competitions?

There are some good tutorial articles at http://community.topcoder.com/tc?module=Static&d1=tutorials&d2=alg_index . It is also worth reading the editorials for past competitions as these contain worked solutions for all their competition problems. http://apps.topcoder.com/wiki/display/tc/Algorithm+P...
by wrongrook
Sun Mar 18, 2012 2:37 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 376
Replies: 21
Views: 5463

Re: problem 376 clarification

I also misread the question initially so here is a clarification that would have helped me and I hope is not considered to spoil the question. Suppose A has a probability of 20% of winning, and a probability of 10% of losing, and there is a 70% probability of a draw. In this case A does NOT have a >...
by wrongrook
Sat Dec 31, 2011 7:15 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 050
Replies: 42
Views: 13441

Re: Project 50

The sum does not have to start with 2.

e.g. 7+11+13 = 31 would be another example.
by wrongrook
Sat Dec 31, 2011 5:04 pm
Forum: News, Suggestions, and FAQ
Topic: Can't see new problem
Replies: 6
Views: 2746

Re: Can't see new problem

Works for me now.
by wrongrook
Sat Dec 31, 2011 4:24 pm
Forum: News, Suggestions, and FAQ
Topic: Can't see new problem
Replies: 6
Views: 2746

Re: Can't see new problem

Same for me, perhaps someone could post the problem here if they can see it?
by wrongrook
Tue Dec 06, 2011 10:20 pm
Forum: Recreational
Topic: Exceptionally difficult questions
Replies: 2
Views: 3057

Re: Exceptionally difficult questions

Thank you very much for your reply, this satisifes my curiosity. (Although I was kind of hoping that someone had suggested a problem (and worked solution) along the lines "What is the smallest N such that if the integers {1, 2, ..., N} are colored, each with one of 2 different colors, then there are...
by wrongrook
Mon Dec 05, 2011 7:34 pm
Forum: Recreational
Topic: Exceptionally difficult questions
Replies: 2
Views: 3057

Exceptionally difficult questions

Out of curiosity I was wondering how often the Project Euler team comes across a question that: 1) is interesting and easy to explain 2) has a nice simple solution (e.g. 15 lines of Python) 3) is considered too hard to be used as a Project Euler problem(!) It is simple enough to find questions that ...
by wrongrook
Sun Nov 20, 2011 2:11 pm
Forum: News, Suggestions, and FAQ
Topic: What are Pythagorean problems?
Replies: 4
Views: 2132

Re: What are Pythagorean problems?

Curiously, according to http://projecteuler.net/award=22;page=20 someone called oldjales has this award despite only having solved a single problem, so perhaps the award just depends on one particular solution?
by wrongrook
Tue Oct 25, 2011 6:25 pm
Forum: Number Theory
Topic: Numbers of the form (1+cX)^1/2
Replies: 8
Views: 4202

Re: Numbers of the form (1+cX)^1/2

You may want to consider this factorisation: z^2 = 1 +cx cx=z^2-1 cx=(z-1)(z+1) For example, suppose c is a prime p. => p|(z-1) or p|(z+1) =>z=kp+1 or z=kp-1 gives all the solutions. (Solutions for x given by x=(z-1)(z+1)/c) If c is composite, then you could consider all factorisations c=a.b You can...