A
sorting algorithm is an
algorithm that puts elements of a
list in a certain
order. The most-used orders are numerical order and
lexicographical order. Efficient
sorting is important for optimizing the use of other algorithms (such as
search and
merge algorithms) which require input data to be in sorted lists; it is also often useful for
canonicalizing data and for producing human-readable output. More formally, the output must satisfy two conditions:
- The output is in nondecreasing order (each element is no smaller than the previous element according to the desired total order);
- The output is a permutation (reordering) of the input.