Company Users

<?php

$infoCompanies = [];

$cmd = explode(' -> ', readline());

while ($cmd[0] !== 'End') {
    list($company, $employee) = $cmd;

    if (!key_exists($company, $infoCompanies)) {
        $infoCompanies[$company] = [];
    }

    if (!in_array($employee, $infoCompanies[$company])) {
        $infoCompanies[$company][] = $employee;
    }

    $cmd = explode(' -> ', readline());
}

ksort($infoCompanies);

foreach ($infoCompanies as $companyId => $users) {
    echo $companyId . PHP_EOL;
    foreach ($users as $user) {
        echo "-- $user" . PHP_EOL;
    }
}