php实现的二分查找算法示例

<?php
$arr = array(4,58,11,34,88,45,32,54,63,78);
function binary($arr,$bnum)
{
 if(is_array($arr) && count($arr) > 0)
 {
 sort($arr);
 $start = 0;
 $end = count($arr)-1;
 $mid = -1;
 while($start <= $end)
 {
  $mid = floor( ($start+$end)/2 );
  if($arr[$mid] == $bnum)
  {
  return $arr[$mid];
  }else if($arr[$mid] < $bnum)
  {
  $start = $mid +1;
  }else if($arr[$mid] > $bnum)
  {
  $end = $mid - 1;
  }
 }
 return -1;
 }
}
$mm = binary($arr,32);
print_r($mm);//输出32
?>