91. Decode Ways(Dynamic Programming with memoization)
So this problem is to find the number of ways one can decode or interpret a string.
The idea is simple:
Recursion:
if(empty string you return a 1: Base Case)
There is a helper function that recurses on the subproblems depending on the 2 conditions:
1. If the starting number and the next number gives a number that is in between 1 and 26 recurse for on 2 substrings starting from i+1 to the end and starting from i+2 to the end.
Else
recurse only on 1 substring i.e i+1 to end.