PHP Simple Choice Sorting algorithm instance _php skill

Simple Choice sorting algorithm: Through the comparison between the N-i, select the smallest key word record from the n-i+1 record and exchange with the first (1<=i<=n) record.

Copy Code code as follows:

<?php
Class sort{
/**
* Simple choice of sorting
*
* @param unknown_type $arr
*/
Public Function Selectsort (& $arr) {
$len =count ($arr);
for ($i =0; $i < $len; $i + +) {
$min = $i;
for ($j = $i +1; $j <= $len-1; $j + +) {
if ($arr [$min]> $arr [$j]) {//If a value is found that is smaller than the $arr[$min], the subscript is assigned to $min
$min = $j;
}
}
if ($min!= $i) {//If $min is not equal to $i, the minimum value is found, the Exchange
$this->swap ($arr [$i], $arr [$min]);
}
}
}
/**
* Position exchange of $a and $b two values
*/
Public function Swap (& $a,& $b) {
$temp = $a;
$a = $b;
$b = $temp;
}
}
$arr =array (4,6,1,2,9,8,7,3,5);
$test =new Sort ();
$test->selectsort ($arr);//Simple selection sort
Var_dump ($arr);
?>

Simple choice of sorting characteristics: The exchange of mobile data is relatively small, thereby saving the corresponding time
Time complexity analysis for simple selection sorting:
Regardless of the best worst-case scenario, the number of comparisons is the same, the I-trip sort needs to be compared with the N-i keyword, at which point N (n-1)/2 times are required. So the ultimate time complexity is O (n^2)
Although the same as the Bubble sort O (n^2), the performance of the select sort is slightly better than the bubble sort.