note 105955 modified in function.array-search by danbrown
| From: | danbrown@php.net | Date: | Tue, 27 Sep 2011 20:27:48 +0000 |
| Subject: | note 105955 modified in function.array-search by danbrown | ||
| References: | 1 | Groups: | php.notes |
| Request: | Send a blank email to php-notes+get-183494@lists.php.net to get a copy of this message | ||
Here is a version of binary search that is done via recursion instead of iteration. Remember that
your data needs to be presorted!
<?php
static function Bin_Search(&$needle, &$haystack, $start, $end) {
if($end < $start)
{
return false;
}
$mid = (int)(($end - $start) / 2) + $start;
if($haystack[$mid] > $needle)
{
return Bin_Search($needle, $haystack, $start, $mid - 1);
}
else if($haystack[$mid] < $needle)
{
return Bin_Search($needle, $haystack, $mid + 1, $end);
}
else
{
return true;
}
}
?>
--was--
Here is a version of binary search that is done via recursion instead of iteration. Remember that
your data needs to be presorted!
static function Bin_Search(&$needle, &$haystack, $start, $end) {
if($end < $start)
{
return false;
}
$mid = (int)(($end - $start) / 2) + $start;
if($haystack[$mid] > $needle)
{
return Bin_Search($needle, $haystack, $start, $mid - 1);
}
else if($haystack[$mid] < $needle)
{
return Bin_Search($needle, $haystack, $mid + 1, $end);
}
else
{
return true;
}
}
http://php.net/manual/en/function.array-search.php