Created
August 28, 2015 12:51
-
-
Save firomero/831397bbf9f05bb083e8 to your computer and use it in GitHub Desktop.
Uncentered Binary Search
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| /** | |
| * Binary Search Uncentered | |
| * This is the method of binary search calculating the exact pivote for the search. | |
| * @param array $haystack | |
| * @param $first | |
| * @param $last | |
| * @param $needle | |
| * @return bool | |
| */ | |
| function binary_search_uncentered(array $haystack, $first, $last,$needle){ | |
| $nterc = round(sizeof($haystack)/3); | |
| if ($first>=$last) { | |
| if ($haystack[$last]==$needle) { | |
| return true; | |
| } else { | |
| return false; | |
| } | |
| } | |
| $nterc = round(($last-$first+1)/3); | |
| if ($needle==$haystack[$first+$nterc]) { | |
| return true; | |
| }elseif($needle<$haystack[$first+$nterc]){ | |
| return binary_search_uncentered($haystack,$first,$first+$nterc-1,$needle); | |
| } elseif ($needle==$haystack[$last-$nterc]) { | |
| return true; | |
| } elseif ($needle<$haystack[$last-$nterc]) { | |
| return binary_search_uncentered($haystack,$first+$nterc+1,$last-$nterc-1,$needle); | |
| } else { | |
| return binary_search_uncentered($haystack,$last-$nterc+1,$last,$needle); | |
| } | |
| return false; | |
| } |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment