Top-Down vs Bottom-Up

In this lesson, we will look at the pros and cons of top-down dynamic programming and bottom-down dynamic programming.

We'll cover the following

Comparison

Both top-down dynamic programming and bottom-up dynamic programming have their own pros and cons. Knowing these pros and cons can help you choose the algorithm’s design approach based on your problem’s requirements.

Operation Top-Down Bottom-Up
Ease of problem formulation ✅ It is easier to formulate a problem in top-down dynamic programming because of its recursive nature Thinking about a problem in a bottom-up manner can be slightly less intuitive
Stack management Stack memory can quickly explode in top-down algorithms, thus making them less practical for larger inputs ✅ In bottom-up algorithms, stack memory is never an issue because there are no recursive calls
Cost of recursion Recursive calls can entail a lot of computation cost ✅ There is no excessive computation cost due to recursive calls
Code readability ✅ Top-down algorithms are typically much easier to read and comprehend Bottom-up algorithms can sometimes be difficult to grasp
Subproblems solved ✅ In top-down algorithms, we only evaluate a result on ad-hoc basis, i.e., when it is needed, meaning results that are not needed are never evaluated Since we evaluate results in order starting from smallest to the largest, we may end up evaluating results that are not needed

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