How does memoization differ from tabulation in dynamic programming?

Memoization involves storing the results of expensive function calls and returning the cached result when the same inputs occur again. Tabulation, on the other hand, builds the table from the ground up, typically using iterative loops. This is a top-down approach, while tabulation is bottom-up, starting from the smallest subproblems. Memoization is often easier to implement but can be less efficient for some problems compared to tabulation.