Explain the concept of a 'Stable' sort.

Explain the concept of a 'Stable' sort.

Approach: Describe preserving the relative order of equal elements.

A sorting algorithm is stable if it preserves the relative order of records with equal keys. If two items have the same key, their order in the sorted output remains the same as in the input.

Follow-up: Is Quicksort stable?

Key concepts: order, equality, mergesort.