Problem 001

[sharkz]

yes and 15 is a multiple of both 3 and 5, and because of that, my program counts it two times (so 2x +15 to sum) - or is this wrong?

[stijn263]

That's wrong, you should only count it once

[wygk123]

The java solution:

{code snipped by hk}

[stijn263]

In particular don't post any code fragments or results.

Besides, your solution seems rather slow when the limit is changed to 10^18

[alto]

I'm almost positive that I did it correctly so if there's someone I could PM what I used to find the answer, that'd be great.

[TripleM]

There's already a thread for problem 1 here: viewtopic.php?f=50&t=965

If you still haven't worked out the problem after reading those 5 pages, feel free to PM me (but not before )

[alto]

They were using c++ as hints but I'm running it in python. I read through all 5 pages and got no tip at all. So I'll PM you the small code

[formicFabricant]

I read through the entire old thread (the one that's unlocked after you give the correct answer) and I couldn't find a single Ruby solution under 60 chars! Honestly...I came up with one in 51 and I'm sure I could do better.

[kevinsogo]

@formicFabricant
Although a very short code is nice and elegant, I don't think it would add much to the discussion.

I've not coded in ruby before but after installing ruby and a few reading I was able to write a 44-character ruby program that solves problem 1. If you're interested I could PM it.

[RodL]

By the sum of multiples of 3 OR 5 we mean to gather the sum of multiples of both 3 and 5 making sure that we only add the LCM of both 3 & 5 once (ex, 15 being the LCM of 3 and 5, we would only add 15 ONCE to the total summation rather than twice when 5*3 is reached.)

I'm getting like 80,000+ as my sum because 3*333 being the top-most multiple that equates to below 1000. But why is the solution much, much lower than 80,000?

If I could PM my code that would be great to someone.

[TripleM]

Please use existing threads if one exists - here's the one for problem 1: viewtopic.php?f=50&t=965

If you've read all 5 pages of that and are still stuck, then (and only then ) you can PM me.

(PS - I'm not sure where you heard the answer was much less than 80000, but that's not true.)

[rayfil]

@RodL

For ease of listing alphabetically and searching in this topic, all problem numbers have 3 digits, using leading 0's for problem numbers under 100.

[SyGeek]

Is it possible to find the answer by adding some of each groups (0-10, 10-20, 20-30 and so on) by following the pattern that each consecutive group has a difference of 47.

70(10-20) - 23(0-10) = 47
117(20-30) - 70(10-20) = 47

[jaap]

Is it possible to find the answer by adding some of each groups (0-10, 10-20, 20-30 and so on) by following the pattern that each consecutive group has a difference of 47.

70(10-20) - 23(0-10) = 47
117(20-30) - 70(10-20) = 47

0-9: 3+5+6+9 = 23
10-19: 10+12+15+18 = 55
20-29: 20+21+24+25+27 = 117
30-39: 30+33+35+36+39 = 173

[SyGeek]

^Just found that I don't have to add 15 x 2 times...Meh, maths is not for me. I'll still try though

[Yemen]

Using python I used a similar brute force solution to many others

Expand

[code]

As you did not snip your code yourself I did (hk)
[/code]

After which I found a simple, elegant, one-line solution

Expand

[code]
As you did not snip your code yourself I did (hk)
[/code]

Although there's probably a way that this can be made simpler and quicker...

[Lord_Farin]

Using python I used a similar brute force solution to many others

Code: Select all

[snip]

After which I found a simple, elegant, one-line solution

Code: Select all

[snip]

Although there's probably a way that this can be made simpler and quicker...

Would you now please take the time and read the BIG RED BOX on top of the page, and act accordingly? Thanks in advance. Please excuse my outburst as you are not the first person to ignore the obvious. Again, this is a publicly visible forum, and people may or may not have already solved problem 1. You are spoiling it for them.

[hk]

Yemen, you're probably new here, but when entering a new place, it would show good manners if you would read the rules before posting.
I sent you a warning.
Please remove your spoilers.

@Lord_Farin: if this kind of behaviour starts irritating you, just ignore. The admins will handle in a few minutes/hours more.

[Lord_Farin]

@Lord_Farin: if this kind of behaviour starts irritating you, just ignore. The admins will handle in a few minutes/hours more.

You are absolutely right. Thanks for stating the obvious. I appreciate what you and the rest of the team go through to keep it enjoyable for everyone. Thanks again.

[hk]

You are absolutely right. Thanks for stating the obvious. I appreciate what you and the rest of the team go through to keep it enjoyable for everyone. Thanks again.

No problem. I'm pleased to keep the site running, even if that means some additional tasks.