Project Euler Forum

Can you tell me if my understanding of the problem is correct? Consider the following example: Suppose the original plain text was "HELLO WORLD", and the encryption key I chose was "97, 98, 99", which are the ascii values for a, b, c, respectively. To encrypt the plain text "HELLO WORLD", I would t...

I seem to be having an issue on this problem. I'm getting the correct answer for S(1000), but my answer is not being accepted for S(1,000,000). I've double and triple-checked my constants and created 3 extra loops to verify values used to calculate N(1,000,000). All 3 loops cleared without reporting...

Site's been down a lot today. Keeping this brief in case...

I appear to be unable to delete private messages. I mark 2 of them, select "Delete marked" and click "Go". I get a message saying "The submitted form was invalid. Try submitting again."

From https://en.wikipedia.org/wiki/Series_and_parallel_circuits In a series circuit, every device must function for the circuit to be complete. If one bulb burns out in a series circuit, the entire circuit is broken. From this problem: The electrical system uses two fuses in series,... For the heati...

I believe the N fuses are replacements. The only circuit has 2 fuses in series. Choose 2 replacements and, if both fuses are good, there's a closed circuit and everything works. Otherwise, there's no power. He keeps trying a different pair until he finds a pair that works.

I don't think people often return to the solution threads. What I've done in the past is ask the question in the solutions thread, then post a message in these forums directing people to the question.

Got it. That's the part I was missing. Thanks.

Am I missing something here? Let's say n=1. Oscar writes "10". Eric can't write any number without exceeding 2. There is one 1. Oscar wins. Yet in the problem statement, Eric guarantees a win.

DanielJackson wrote: ↑

Wed Feb 19, 2020 11:28 pm

n = a*b, a > b
Let n = 15 = 15*1 = 5*3
1. a = 15, b = 1 => d = 4, 19^2 - 15^2 - 11^2 = 15
2. a = 5, b = 3 => d = 2, 7^2 - 5^2 - 3^2 = 15
n = 15 has exactly 2 solutions and 15 < 27 (by condition). Where am I wrong?

$5^2-3^2-1^2=15$. 15 has at least 3 solutions.

I probably should have noted when this happened, but one of my last times attempting to access the forums, I instead got something on the bottom of the screen asking "What do you want to do with index.php?", giving me the option to open, save, or cancel. And now when I try to pin or unpin a problem,...

What "new plates"? You take n plates and divide them into k piles. For each calculation of f(n,k), the total number of plates is fixed.

I think the way the sentence is structured can cause confusion. Namely

a 31K text file containing a 80 by 80 matrix, from the left column to the right column.

This could be interpreted to mean the matrix is given one column at a time.

This site's been down quite a bit lately it seems. Some sort of SQL error, not always the same each time.

The program was working correctly. All the hand calculations were correct. One simple mistake on a limit of summation threw everything else off. My thanks to RobertStanforth for lending an ear. If I hadn't had to lay everything out to someone else, regardless of whether or not he actually reads all ...

At this point, I'm about 1 step away from challenging the answer to this problem. I know a fair number of people have already solved this problem. I know I have everything in correctly, the program appears to operate just fine. I've done just about everything I can. Next step is to verify each step ...

One more thing. Has anyone else noticed the images in people's signatures aren't displaying? I went into my profile to find the source of the image and tried opening it in another browser tab and got: Not Found The requested URL was not found on this server. Additionally, a 404 Not Found error was e...

when starting with A3 you basically start with 1 piece A4 and 1 piece A5, leaving 2 possible options: - pick A4 first -> cut in half, now you have 2 A5 pieces (outside the envelope, the other one is still inside), pick 1 and put the rest back, so the envelope contains only two A5 pieces. Next step ...

Not sure why my solution is so slow. I've posted in the solutions thread. If someone could view it and give me their insights as to why it seems so much slower than similar solutions (either through a pm or in the solution thread), it would be much appreciated.

I had something similar for these message boards maybe 2 or 3 weeks ago. Which begs the question, "How do we make someone aware of a problem with the message boards when we can't access them?"