PHP based on the binary method to implement array lookup function example explained

This article mainly introduces PHP based on the binary method to realize the array lookup function, combined with the example form analysis of while loop and recursive call algorithm implementation of binary search function of the relevant implementation skills, the need for friends can refer to the following

In this paper, we describe the implementation of the array lookup function based on the binary method of PHP. Share to everyone for your reference, as follows:

Dichotomy method. Methods that use the while loop and recursive invocations, respectively.

<?php//the use of the array must be ordered, or ascending, or descending $arr = Array (1, 3, 5, 7, 9, 13);//recursive invocation (compared to better understanding function Bsearch_r ($v, $arr, $low, $high)  {if ($low > $high) {//return-1 to determine the end condition first;  } $i = Intval (($high + $low)/2); if ($arr [$i] > $v) {return Bsearch_r ($v, $arr, $low, $i-1);//recursion} else if ($arr [$i] < $v) {return Bsearch_r (  $v, $arr, $i +1, $high);  } else {return $i; }}echo bsearch_r (1, $arr, 0, Count ($arr)-1);//0echo ' 

Operation Result:



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