Dynamic Programming: Memoization vs Tabulation

Breaking Down Dynamic Programming

DP is often considered the hardest topic in interviews, but it boils down to two concepts: Overlapping Subproblems and Optimal Substructure.

Approaches

1. Top-Down (Memoization): Write a recursive function and cache the results of subproblems in a hash map or array. Easier to conceptualize.
2. Bottom-Up (Tabulation): Build a table iteratively from the base cases up to the target. Avoids recursion stack overhead.

Classic DP Problems

• 0/1 Knapsack Problem
• Longest Common Subsequence
• Matrix Chain Multiplication