Measure the actual performance of your dynamic programming function for finding the longest common substring, for a range of suitable inputs. If you find that you get errors because of too much depth of recursion for large values of L and R$,$ you can check and amend the current recursion limit on your system using the following Python code:

import sys

print$(\text{'}$Current recursion limit is$\text{'},$ sys$.$getrecursionlimit$())$ sys$.$setrecursionlimit$(3000)$ # Change this $\text{'}3000\text{'}$ to any sufficiently large integer value print$(\text{'}$Check: new recursion limit is$\text{'},$ sys$.$getrecursionlimit$())$