rio.php

<?php

// 六村リオ

# コーヒーを$amount味見をする
function drinkCoffee($amount)
{
    global $water;
    global $coffee;
    // 味見をする量の方が多い場合は量は0となる
    if ($water + $coffee < $amount) {
        $water = 0;
        $coffee = 0;
    } else {
        $t_water = $water - $amount * $water / ($water + $coffee);
        $coffee -= $amount * $coffee / ($water + $coffee);
        $water = $t_water;
    }
}

// 変数
$water = 0;
$coffee = 0;

// 入力行数
$count = trim(fgets(STDIN));

for ($i = 0; $i < $count; ++$i) {
    // input command
    $command = explode(' ', trim(fgets(STDIN)));
    switch ($command[0]) {
        case '1':
            $water += $command[1];
            break;
        case '2':
            $coffee += $command[1];
            break;
        case '3':
            drinkCoffee($command[1]);
            break;
        default:
            break;
    }
}
// print concentration
$amount = ($water + $coffee == 0) ? 1 : $water + $coffee;
echo floor(100 * $coffee / $amount) . "\n";