<?php

function cut(int $total) {
    $result = [];

    while ($total > 0) {
        $new = random_int(1, $total);
        $result []= $new;
        $total -= $new;
    }

    shuffle($result);
    return $result;
}

function repr_array(array $arr) {
    $result = [];

    foreach ($arr as $item) {
        $result []= $item;
    }

    return '['.implode(', ', $result).']';
}

$max = random_int(100000, 500000);
echo $max, ' = ', repr_array(cut($max)), "\n";