Sorting and Selection

Abstract

Telephone directories are sorted alphabetically by last name.Why? Because a sorted index can be searched quickly. Even in the telephone directory of a huge city, one can find a name in a few seconds. In an unsorted index, nobody would even try to find a name. This chapter teaches you how to turn an unordered collection of elements into an ordered collection, i.e., how to sort the collection. The sorted collection can then be searched fast. We will get to know several algorithms for sorting; the different algorithms are suited for different situations, for example sorting in main memory or sorting in external memory, and illustrate different algorithmic paradigms. Sorting has many other uses as well.