Recursion

Permutations

From Wikipedia:

Permutation is the arrangement of symbols or objects into distinguishable orderings. Each unique ordering is called a permutation.[1] For example, with the numerals one to six, each possible ordering consists of a complete list of the numerals, without repetitions. There are 720 total permutations of these numerals, one of which is: "4, 5, 6, 1, 2, 3".

The general concept of permutation can be defined more formally in different contexts. In set theory, a permutation is an ordered sequence containing each symbol from a set once and only once; neither "1, 2, 2, 3, 4, 5, 6" nor "1, 2, 4, 5, 6" are permutations of the set "1, 2, 3, 4, 5, 6."

A permutation can be a rearrangement of letters in a word. For example, the permutations of 'log' are:

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Recursion Search, Data Structures