Classic 2D DP on strings.

Overview

Classic 2D DP on strings.

Example 

  int[] memo = new int[n + 1];
Arrays.fill(memo, -1);
// Top-down memoization pattern

Common Use Cases

  • Optimization problems
  • Counting problems
  • String transformation

Pitfalls to Avoid

  • Not identifying state variables
  • Wrong base cases
  • Recursion
  • Greedy algorithms comparison

Best Practices

  • Understand when to use longest common subsequence versus simpler alternatives
  • Write unit tests covering edge cases and failure paths
  • Follow Java conventions and prefer standard library APIs when available
  • Profile before optimizing — measure impact in your specific workload