A Repeat of Pi (ambiguity)

Allosentient · Post by **Allosentient** » Sat Jun 07, 2008 6:37 pm

I am trying to figure out exactly what kind of repeating sequence you are looking for. I know it is not something like 1111111 since that would be too easy.

I tried searching for a string of x length that appears more than once in the sequence, but that either didn't find an answer or ate an extreme amount of cpu.

Now I am trying to find something such as 123456123456 (appearing consecutively). I know it must be at least 12 digits (there was more than one that was 10 digits). but that is also eating a lot of cpu and I do not even know if I am doing this the correct way.

Sorry to ask so many questions but hopefully this will help anyone else who might have a similar problem

Post by **adum** » Sat Jun 07, 2008 9:05 pm

you're looking for any repeated sequence.

so if your digits were
123654323653

your answer would be '2365'

some approaches will require more cpu time than others =)

good luck,
adum

the_impaler · Post by **the_impaler** » Sat Jun 21, 2008 6:09 am

Can the sequences overlap ? E.g. 234562345623456 can be treated as 2345623456 twice with overlapping and 23456 3 times without overlapping.

Post by **adum** » Sat Jun 21, 2008 5:16 pm

the sequence can overlap, but i'll give you the hint that it's pretty unlikely on a random sequence of digits =)

adum

haX0r1337 · Post by **haX0r1337** » Tue Dec 01, 2009 9:45 pm

How many digits have the answer? > 10 ?
(Sorry for bad english).

smutley · Post by **smutley** » Tue Dec 01, 2009 9:57 pm

That is part of the challenge to find out. And is it important to know?

haX0r1337 · Post by **haX0r1337** » Wed Dec 02, 2009 7:13 am

Yes it's important.
Then my program runs faster.

DaymItzJack · Post by **DaymItzJack** » Wed Dec 02, 2009 12:42 pm

Then do something smart and you'll get the right answer fast.

laz0r · Post by **laz0r** » Fri Mar 12, 2010 10:15 pm

Can anyone confirm that for sequences first appearing in the first hundred thousand digits, there are several candidates with the top length 10 digits?

megabreit · Post by **megabreit** » Sat Mar 13, 2010 1:06 am

I can't confirm that, but it's likely, that there are some candidates with 10 digits length. Why do you want to know that? The challenge scope is 1 million digits and with today's computing power (and the right algorithm) it's possible to search 1 million digits nearly as fast as 100000 digits...

laz0r · Post by **laz0r** » Sat Mar 13, 2010 10:17 am

I don't think I have the right algorithm... for each digit, I'm going through the longest repeating sequence from that digit. It's taking a very long time to go through all the digits.

laz0r · Post by **laz0r** » Sat Mar 13, 2010 12:36 pm

Ah! Got it now. Better algorithm

moose · Post by **moose** » Wed Jul 27, 2011 12:14 pm

Lets make a rather short example. For 100 digits of pi the correct solution would be 592, would it?

laz0r · Post by **laz0r** » Wed Jul 27, 2011 2:28 pm

moose wrote:Lets make a rather short example. For 100 digits of pi the correct solution would be 592, would it?

Indeed

Thu Jul 28, 2011 4:24 pm

moose wrote:Lets make a rather short example. For 100 digits of pi the correct solution would be 592, would it?

If my program works correctly, your answer is not wrong, but incomplete:

Code: Select all

i:  3, j: 60, search_length: 3, pattern match: 592 592
i: 71, j: 81, search_length: 3, pattern match: 628 628
i: 73, j: 80, search_length: 3, pattern match: 862 862

hacker.org

A Repeat of Pi (ambiguity)

A Repeat of Pi (ambiguity)

Confirmation