How to implement binary search in php

php method to implement binary search: first use a certain value in the array as the boundary; then search recursively until the end, the code is [if ($low <= $high){$mid = intval (($low $high)/2);if ($array[$mid] == $k)】.

The operating environment of this tutorial: Windows 7 system, PHP version 5.6, DELL G3 computer. This method is suitable for all brands of computers.

How to implement binary search in php:

Idea: Use a certain value in the array as the boundary, and then search recursively until the end.

Code 1

<?php
function find($array, $low, $high, $k){
  if ($low <= $high){
  $mid = intval(($low+$high)/2);
    if ($array[$mid] == $k){
    return $mid;
  }elseif ($k < $array[$mid]){
    return find($array, $low, $mid-1, $k);
    }else{
    return find($array, $mid+1, $high, $k);
    }
  }
  die(&#39;Not have...&#39;);
}
//test
$array = array(2,4,3,5);
$n = count($array);
$r = find($array,0,$n,5)

1. Think about the last critical situation: line 13, return false is indeed written here, I thought it right

2. How to use die : Line 13, die terminates the program

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