An algorithm is a procedure used for solving a problem or performing a computation. An algorithm act as a precise list of instructions that conduct specified actions step by step in either hardware- or software-based routines.

There are several types of algorithms, all designed to accomplish different tasks. For example, algorithms can perform the following:

- Search engine algorithm: This algorithm takes search strings of keywords and operators as input, searches its associated database for relevant webpages, and returns results.
- Encryption algorithm: This computing algorithm transforms data according to specified actions to protect it. A symmetric key algorithm, such as the Data Encryption Standard, for example, uses the same key to encrypt and decrypt data. As long as the algorithm is sufficiently sophisticated, no one lacking the key can decrypt the data.
- Greedy algorithm: This algorithm solves optimization problems by finding the locally optimal solution, hoping it is the optimal solution at the global level. However, it does not guarantee the most optimal solution.
- Recursive algorithm: This algorithm calls itself repeatedly until it solves a problem. Recursive algorithms call themselves with a smaller value every time a recursive function is invoked.