Chapter IV.2. Searching Algorithms

One of the most common functions of a computer program is searching. A database needs to search through names and addresses, a word processor needs to search through text, and even a computer chess game needs to search through a library of moves to find the best one.

Because searching is such an important part of computer programming, computer scientists have developed a variety of algorithms to search for data. When searching for data, the main limitation is time. Given enough time, any search algorithm can find what you want, but there's a big difference between finding data in five seconds or five hours.

The time a search algorithm takes is always related to the amount of data to search, which is the search space. The larger the search space, the slower the search algorithm. If you only need to search a small search space, even a simple and slow search algorithm is fast enough.

The two main categories of search algorithms are

  • Uninformed (or brute-force)

  • Informed (or heuristic)

Uninformed, or brute-force, search algorithms work by simply examining the entire search space, which is like losing your car keys in your apartment and searching every apartment in the entire building. Eventually, you find your keys, but it may take a long time to do it.

Informed, or heuristic, search algorithms work by selectively examining the most likely parts of the search space. This is like losing your car keys in your apartment but only examining the bedroom where you ...

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