Binary search (1)
Assume that the (sub)array is sorted.
Consider searching a dictionary for a target word.
Bad idea: Look at page 1, then page 2, etc., until you find the page containing the target word. That is linear search!
Better idea: Choose a page near the middle. If the target word happens to be on that middle page, we’re finished. If the target word is less (greater) than the words on that middle page, focus on the pages before (after) that middle page, and repeat. That is binary search.