Question

1. Describe a linear search (explain how it works).

Answer 1

1. A linear search searches on a straight path, hence the term “linear”. So a linear search would search from a one index to another in a straight path. For example, a linear search of an array, if given given the first and last index of the array, would search it one index after the other. First it would check index 0, then index 1, then index 2, and so forth.

2. A linear search can be useful if you are trying to find more than one instance of an value in a data structure. Since you want to search the whole array for each instance of the object or value.

3. A binary search only works with sorted data structures. It takes a data structure, finds its mid point, and checks I see if the value it is looking for is greater, less than, or equal to the midpoint value. If it is equal to the midpoint value, it’s finished and the search function is over.
If it’s greater than the midpoint, it disregards the lower half of the data structure and focuses on the upper half. If it’s less than the mid point then it disregards the upper half and focuses on the lower half.
It then repeats what it did at the beginning of the search function to again narrow down the amount of searching that needs to be done. In other words, if it disregarded the lower half of the data structure in the first part of the search, it finds the midpoint of the upper half of the data structure, checks to see if the value it’s looking for is greater than, less than, or equal to the midpoint. If it’s equal to it the searching is done, if it’s greater it disregards the lower half of the upper data structure, and repeats the process.
It will continue to do this until either the value is found or the value is not found.

4. You would use binary search if you are searching for one specific value in a sorted data structure.

5. A binary search must have a sorted data structure for it work.

6. Binary search is more efficient because the cost to run a binary search is substantially less than running a linear search.