<?php
$array=array(-2,11,-4,13,-5,-2);

function find_son_set($array)
{
    $length=count($array);
    foreach ($array as $key => $value)
    {
        for ($i=$key+1; $i < $length; $i++)
        {
            $tmp_arr=array_slice($array,$key,$i-$key);
            $implode=implode(",",$tmp_arr);
            $list[$implode]=array_sum($tmp_arr);
        }
    }
    arsort($list);
    return array("son"=>key($list),"sum"=>current($list));
}
var_dump(find_son_set($array));