"Data Structure" PHP implementation lookup table

Data | structure

"Basic Algorithm"

Suppose you have an array, you need to find out where the value is in the array.

<?
Binary lookup
Function Bin_sch ($array, $low, $high, $k) {
    if ($low <= $high) {
         $mid = Intval (($low + $high)/2);
        if ($array [$mid] = = $k) {
             return $mid;
       }elseif ($k < $array [$mid]) {
             return Bin_sch ($array, $low, $mid-1, $k);
       }else{
             return Bin_sch ($array, $mid +1, $high, $k);
       }
   }
    return-1;
}

Sequential Lookup
function Seq_sch ($array, $n, $k) {
$array [$n] = $k;
for ($i =0; $i < $n; $i + +) {
if ($array [$i]== $k) {
Break
}
}
if ($i < $n) {
return $i;
}else{
return-1;
}
}

?>

Test code:
The Array.txt file contains 1 million data such as 2,3,4,5, which is determined by sequential lookup and binary lookup.

Two-point Search
<?php
Set_time_limit (0);
$array = Array ();
$file = file_get_contents ("./array.txt");

$array = Explode (",", $file);
Sort ($array);

$st = time ();
$k = 43;
$n = count ($array);
$r = Bin_sch ($array, 0, $n-1, $k);
$et = time ();

$t = $et-$st;
echo "Process time:". $t. " /S ";
?>

Above output: Process time:0/s

Sequential Lookup
<?php
Set_time_limit (0);
$array = Array ();
$file = file_get_contents ("./array.txt");
$array = Explode (",", $file);

$st = time ();
$k = 43;
$n = count ($array);
$r = Seq_sch ($array, $n, $k);
$et = time ();

$t = $et-$st;
echo "Process time:". $t. " /S ";
?>

Above output: Process time:9/s

It's easy to see who's high in efficiency.

"Algorithmic Improvement"

;?
//Two-point lookup (recursive elimination)
function Bin_sch ($array, $n, $k) {
    $low = 0;
    $high = $n-1;
    while ($low <= $high) {
        $mid = intval ($high-$ Low)/2);
        if ($array [$mid] = = $k)
             return $mid;
        ElseIf ($k < $array [$mid]) {
             $high = $mid-1;
       }else{
             $low = $mid + 1;
       }
   }
    return-1;
}

Sequential lookup (Improved version)
function Seq_sch ($array, $n, $k) {
$array [$n] = $k;
for ($i =0; $i + +) {
if ($array [$i]== $k) {
Break
}
}
if ($i < $n) {
return $i;
}else{
return-1;
}
}
?>

Can you see how the above two functions have changed? How much efficiency has been raised?