数据结构和算法——选择排序

$numbers = [21,25,100,98,89,77];

FOR each element of the master list indexed by i
 
    Set current element of master list as the sub-list[i] element
 
    Find the smallest item from the master list (staring from i)
 
    Swap it with the last element of sub-list
 
END FOR

<?php
$masterList = [21, 25, 100, 98, 89, 77];
 
$subList = [];
 
for ($i = 0; $i < count($masterList); $i++) {
 
    $subList[$i] = $masterList[$i];
 
    // Find the smallest item
    $smallestIndex = $i;
 
    for ($j = $i; $j < count($masterList); $j++) {
        if ($masterList[$j] < $masterList[$smallestIndex]) {
            $smallestIndex = $j;
        }
    }
    // 交换
    $tmp = $subList[count($subList) - 1];
    $subList[count($subList) - 1] = $masterList[$smallestIndex];
    $masterList[$smallestIndex] = $tmp;
}
 
print_r($subList);
 
// Output:
/*
Array
(
    [0] => 21
    [1] => 25
    [2] => 77
    [3] => 89
    [4] => 98
    [5] => 100
)
*/