Quicksort
In plain terms
A fast divide-and-conquer sorting algorithm built around a pivot.
Going deeper
Quicksort picks a pivot, partitions items into smaller and larger groups, then recursively sorts each. It averages very fast performance in place, though a bad pivot choice can degrade it.
Under the hood
Average O(n log n), worst-case O(n²) on bad pivots; randomized or median-of-three pivots and introsort (falling back to heapsort) avoid the worst case. In-place but not stable.
Examples
Default sort in many standard libraries (often introsort), partitioning workloads.
Think of it like...
Like sorting a deck by picking one card and splitting the rest into 'lower' and 'higher' piles, then repeating within each pile.