Ordered list search

- [Narrator] Searching for data in an ordered,…or sorted list, is much more efficient…than for an unordered list.…And that's because we have a valuable piece of information…about the list and the items in it,…which is the fact that it's sorted.…With a sorted list, we can perform a type of search…is called a binary search.…So, let's imagine we had a list of sorted numbers,…and the number that we're searching for is the number 41.…To perform the binary search,…we start off with two indexes…at the beginning and end of the list,…and then we calculate the midpoint of the list,…rounded down in case of an uneven division,…and then we check to see if that value at the midpoint…is the value that we want,…and if it is, then great, we return that index.…

Now, if the number at that index is less…than the one that we're searching for,…we know that we can ignore all the numbers below that index,…and conversely if that number is larger…than the one we're looking for,…we can ignore all the numbers above that index.…So, now we calculate the new midpoint by advancing,…