Permutation

A permutation is a way of arranging n distinct elements in a single row. In a permutation, the order of the elements matters: even if the same elements are used, arrangements in a different order are counted as different. For example, when arranging three different fruits (an apple, a banana, and an orange), apple-banana-orange and banana-orange-apple are different permutations. Permutations are used not only in mathematical theory but also in many other fields, such as combinatorial problems, statistics, and cryptography.