Given an item X and a collection of items, determine whether or not
X is in the collection.
The collection can be an array or some other type of collection
The items can be numbers or strings or any kind of data structure
For simplicity, we'll assume that our collection is held in an array
Check each array element in turn until you find it.
We say that linear search runs in linear time.
If we have N items in our collection, it could take us as many as
N tries to find the item and it would definitely take us N tries
to find out that it was not among the items in the collection.
Would it help if the collection were sorted first ?
Assume the elements are sorted
See the phone-book demolition in lecture for a demonstration
of the algorithm.
We say that binary search runs in "log N" time.
If there are N items in our sorted collection, it can take as
long as log2N to find it or rule out its presence.
Wow! That's fast !!!
Comparing the two
Linear search requires between 1 and n comparisons/array accesses.
Binary search requires between 1 and log2(n)