Python - how to find all intersections of two strings?

Question

How to find all intersections (also called the longest common substrings) of two strings and their positions in both strings?

For example, if S1=\"never\"

Answer 1

Well, you're saying that you can't include any library. However, Python's standard difflib contains a function which does exactly what you expect. Considering that it is a Python interview question, familiarity with difflib might be what the interviewer expected.

In [31]: import difflib

In [32]: difflib.SequenceMatcher(None, "never", "forever").get_matching_blocks()
Out[32]: [Match(a=1, b=3, size=4), Match(a=5, b=7, size=0)]


In [33]: difflib.SequenceMatcher(None, "address", "oddness").get_matching_blocks()
Out[33]: [Match(a=1, b=1, size=2), Match(a=4, b=4, size=3), Match(a=7, b=7, size=0)]

You can always ignore the last Match tuple, since it's dummy (according to documentation).