July 1961

Tony Hoare publishes Quicksort

Tony Hoare published the QuicksortA divide-and-conquer sorting algorithm — average O(n log n) and still taught in every algorithms course. algorithm in July 1961 — a divide-and-conquer sorting method still taught in every algorithms course.

What it was for

Tony HoareQuicksortA divide-and-conquer sorting algorithm — average O(n log n) and still taught in every algorithms course. became the default in-memory sort in standard libraries and a interview staple — average O(n log n) with elegant recursion. Hoare conceived it while working on machine translation sorting at Moscow State University.

People

  • Tony Hoareresearcher

Why it's here

QuicksortA divide-and-conquer sorting algorithm — average O(n log n) and still taught in every algorithms course. is among the most influential algorithms in computer science education and practice.

Why it mattered

It demonstrated divide-and-conquer sorting with in-place performance.

What it solved

Sorting large datasets on tape and memory required faster than O(n²) methods.

Media

  • Tony Hoare
    ImageTony Hoare

    Rama, CC BY-SA 2.0, via Wikimedia Commons