perl-List-BinarySearch

A binary search searches sorted lists using a divide and conquer
technique. On each iteration the search domain is cut in half, until the
result is found. The computational complexity of a binary search is
O(log n).
The binary search algorithm implemented in this module is known as a
Deferred Detection variant on the traditional Binary Search. Deferred
Detection provides stable searches. Stable binary search algorithms have
the following characteristics, contrasted with their unstable binary search
cousins:

In the case of non-unique keys, a stable binary search will always
return the lowest-indexed matching element.  An unstable binary search
would return the first one found, which may not be the chronological first.

Best and worst case time complexity is always O(log n).  Unstable
searches may stop once the target is found, but in the worst case are
still O(log n).  In practical terms, this difference is usually not
meaningful.

Stable binary searches only require one relational comparison of a
given pair of data elements per iteration, where unstable binary searches
require two comparisons per iteration.

The net result is that although an unstable binary search might have
better "best case" performance, the fact that a stable binary search gets
away with fewer comparisons per iteration gives it better performance in the
worst case, and approximately equal performance in the average case. By
trading away slightly better "best case" performance, the stable search gains
the guarantee that the element found will always be the lowest-indexed
element in a range of non-unique keys.


This module has a companion "XS" module: the List::BinarySearch::XS
manpage which users are strongly encouraged to install as well. If
List::BinarySearch::XS is also installed, 'binsearch' and 'binsearch_pos'
will use XS code. This behavior may be overridden by setting
'$ENV{List_BinarySearch_PP}' to a true value. Most CPAN installers will
either automatically install the XS module, or prompt to automatically
install it. See CONFIGURATION for details.

          

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License: Artistic-1.0 OR GPL-1.0-or-later
URL: https://metacpan.org/release/List-BinarySearch