1. Mergesort

2. Bottom up vs top down Typical mergesort (top-down) Traversal:
Post-order
The top levels are a power of 2

3. Bottom up vs top down Bottom-up mergesort Traversal: level-order
All inputs apart from the final one are a power of 2

4. Bottom up vs top down Bottom up: creates sorted sub-inputs
Top down: sorts half input and proceeds to the other half
Bottom up / top down

5. Bottom up with various input types
Random, small range, almost sorted, almost reversely sorted, many duplicates
Time to execute: independent of input type, depends only on input size