largest substring of two strings, no recursive bs.

No.12842107 ViewReplyOriginalReport
Hey /sci \cap /g.
Here's two strings comprised of 4 distinct symbols, {G,T,A,C}

The first one, let's call it A
https://ghostbin.com/paste/r4m7g

The other one, let's call it B
https://ghostbin.com/paste/CJnWi

I am struggling to find the longest common substring to both. No, this is not my homework. And yes, it is what you think it is.

As it goes, the common substring is said to be over 1000 chars long.
Any code to confirm this?