Linear vs binary search: why 30 guesses can beat a billion

Need to find one item in a list? You can check every item in turn (linear search), or, if the list is sorted, look at the middle and throw away half each time (binary search).

The difference is enormous. On a billion items, linear search may need a billion checks; binary search never needs more than 30, because doubling the list adds just one step.

Play guess-my-number, race both methods side by side, and read a short Python version of each.