$0\mathrm{.}2$ Binary search

Linear search may require searching all list elements, which can lead to long runtimes. For example, searching for a contact on a smartphone one$-$by$-$one from first to last can be time consuming. Because a contact list is sorted, a faster search, known as binary search, checks the middle contact first. If the desired contact comes alphabetically before the middle contact, binary search will then search the first half and otherwise the last half. Each step reduces the contacts that need to be searched by half.