Created
August 28, 2015 12:53
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Binary Search Uncentered Callback
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| /** | |
| * Binary Search Uncentered with Callback | |
| * This is the method of binary search calculating the exact pivote for the search. | |
| * @param array $haystack | |
| * @param $first | |
| * @param $last | |
| * @param $needle | |
| * @param callable $callback | |
| * @return bool | |
| */ | |
| function binary_search_uncentered_callable(array $haystack, $first, $last,$needle, callable $callback){ | |
| $nterc = round(sizeof($haystack)/3); | |
| if ($first>=$last) { | |
| if ($callback($haystack[$last])==$callback($needle)) { | |
| return $last; | |
| } else { | |
| return -1; | |
| } | |
| } | |
| $nterc = round(($last-$first+1)/3); | |
| if ($callback($needle)==$callback($haystack[$first+$nterc])) { | |
| return $first+$nterc; | |
| }elseif($callback($needle)<$callback($haystack[$first+$nterc])){ | |
| return binary_search_uncentered($haystack,$first,$first+$nterc-1,$needle); | |
| } elseif ($callback($needle)==$callback($haystack[$last-$nterc])) { | |
| return $last-$nterc; | |
| } elseif ($callback($needle)<$callback($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; | |
| } |
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