<?php

function minmax($a)
{
    $valmin = min($a);
    $valmax = max($a);
    return array(
        "min" => $valmin,
        "max" => $valmax
    );
}

print_r(minmax(array(
    "maxime" => 1,
    "coutteau" => 24,
    "jean" => 5,
    "claude" => 9,
    "nunes" => 10,
    "david" => 2222,
    "gatel" => 291,
    "frederic" => 20
)));