LeetCode 72 Edit Distance - Problem Statement

This is Edit Distance from LeetCode, also called Levenshtein Distance. Given two strings, find the minimum operations to convert one to the other. You can insert, delete, or replace a character. For "horse" and "ros": horse → rorse → rose → ros. $3$ operations.

Constraints: $m, n \le 500$. Brute-force recursion is exponential. Build up answers for shorter prefixes first to avoid recomputation.