Tabulation and memoization are both optimization techniques employed, especially in the domain of algorithms and computation. However, they have different approaches and uses. Using Ruby, a language known for its expressiveness, we can demonstrate and differentiate the two.

## Tabulation:

*What is Tabulation?*

Tabulation is a bottom-up dynamic programming technique where you solve all the subproblems first. You then use the solutions of these subproblems to build the solution to bigger problems.

## Approach in Ruby:

Let’s consider the classic problem of computing the nth Fibonacci number.

`def fibonacci(n)`

return n if n <= 1

table = [0, 1]

(2..n).each do |i|

table[i] = table[i - 1] + table[i - 2]

end

table[n]

end

In the above example, we use an array **table** to store solutions to subproblems. We then combine these solutions to find the desired Fibonacci number.

## Memoization:

*What is Memoization?*

Memoization is a top-down dynamic programming technique where you break down a problem into subproblems. It involves storing the result of expensive function calls and returning the cached result when the same inputs occur again.