Glossary

Canonical terms for this subject. Every lesson uses these words.

Pass

One left-to-right walk comparing every adjacent pair in the unsorted prefix. Avoid: iteration, round, sweep.

Swap

Exchanging two adjacent elements because the left is strictly greater. Three writes.

Loop invariant

A statement true before the loop and after every pass. Here: after pass k, the last k positions are final.

Fixed suffix

The last k positions after pass k. Never compared again. Avoid: sorted part, done area.

Early exit

Stopping after a pass with zero swaps, since zero swaps proves the array is sorted. Gives O(n) best case.

Inversion

A pair of elements out of order. Each swap removes exactly one.

Stable

Equal keys keep their original relative order after sorting. Bubble sort is stable because it uses strict greater-than.

Quadratic, O(n²)

Work grows with the square of input size: 10x input, 100x work.

Terms promoted here as lessons cover them; definitions may tighten as understanding deepens.