Distinct Subsequences | Leetcode 115 | Live coding session

Here is the solution to "Distinct Subsequences" leetcode question. Hope you have a great time going through it.

1) 0:00 Explaining the problem out loud
2) 1:10 Algorithm walkthrough
3) 2:00 Solution approach
4) 18:00 Coding

For discussion/feedback

PS : Please increase the speed to 1.25X

[rimjhimmoitra]

Thanks a bunch! dp seemed hard but no more, very well explained.

[sajan]

Very well explained keep it up mahn!!!

[aarindey]

what is the intuition behind the process?

[kabilanm]

bro, we don't need the filling of the whole table, we need how you do come up with DP states in match and mismatch case ?.. that thinking we need..please explain like that. and using int is not passing the solution

[guptagaurav]

Bro, I know how to solve such questions using recursion TopDown approach, but how to memoize it doesnt come naturally to me.
Nevertheless your video cleared my doubt how to do it using BottomUp. Thanks!

[kaushalaggarwal]

I am getting runtime error due to int overflow but the ques mentions the answer would fit in 32 bit integer, any possible error??

[bliewhale]

Where does the question give the hint we have to use DP with 2D array? My first instinct was to use pointers/Sliding window. Is there some key words to identify a DP problem?