Halve

a hundred suspects. seven questions. always.

find 1-of-100 — each guess halves the world

Guessing the midpoint and cutting the remaining range in half, every time, finds any number from 1 to 100 in at most seven tries — compare that to checking candidates one at a time, which averages fifty guesses. It’s binary search, felt as a hand motion instead of read as an algorithm.

Concepts: binary-search, information.

An interactive you play with one thumb, on Wundr.