计数排序的PHP实现 Counting sort

计数排序(Counting sort)的PHP实现

set_time_limit(1);
//error_reporting(0);
function out_arr($arr) {
    return implode(', ', $arr).'
';
}

function sort_counting($arr) {
    $min = min($arr);
    $max = max($arr);

    $count = array();
    for($i = $min ; $i <= $max; $i++ ) {
        $count[$i] = 0;
    }

    foreach ($arr as $v) {
        $count[$v] = $count[$v]+1;
    }

    foreach ($count as $k => $c) {
        for($i = 0 ; $i < $c; $i++ ) {
            $ret[] = $k;
        }
    }

    return $ret;
}

echo '<pre>';
$arr = range(1, 20);
shuffle($arr);
echo 'ORG : '.out_arr($arr);
$arr = sort_counting($arr);
echo 'RET : '.out_arr($arr);
echo '</pre>';