Finding Substring Using Python

In this lecture we'll discuss problem about finding subsequences of any given sequence.

let's discuss what it is actually about.

Whats subsequence?
Subsequence is basically set of the elements present in that sequence, in the same order that they appear in the sequence.
So problem is to find all possible subsequences for given sequence, which is string in our case.
for example,
we have a string abc.

subsequences for this string will be a, then ab, then abc, then b, bc, c. also we include empty string as one of the valid subsequence.