PHP抽奖算法

<?php
function get_reward($proArr = array())
{
    $proSum = array_sum($proArr);
    foreach ($proArr as $key => $productCur) {
        $randNum = mt_rand(1, $proSum);
        if ($randNum <= $productCur) {
            $result = $productCur;
            break;
        } else {
            $proSum -= $productCur;
        }
    }
    unset($proArr);
    return $result;
}

foreach ($prize_arr as $key => $val) {
    $arr[$val['id']] = $val['v'];
}

$rid = get_rand($arr); //根据概率获取奖项id

$res['yes'] = $prize_arr[$rid - 1]['prize']; //中奖项
unset($prize_arr[$rid - 1]); //将中奖项从数组中剔除，剩下未中奖项
shuffle($prize_arr); //打乱数组顺序
for ($i = 0; $i < count($prize_arr); $i++) {
    $pr[] = $prize_arr[$i]['prize'];
}
$res['no'] = $pr;
echo json_encode($res);

$prize_arr = array(
    '0' => array('id' => 1, 'prize' => '平板电脑', 'v' => 1),
    '1' => array('id' => 2, 'prize' => '数码相机', 'v' => 5),
    '2' => array('id' => 3, 'prize' => '音箱设备', 'v' => 10),
    '3' => array('id' => 4, 'prize' => '4G优盘', 'v' => 12),
    '4' => array('id' => 5, 'prize' => '10Q币', 'v' => 22),
    '5' => array('id' => 6, 'prize' => '下次没准就能中哦', 'v' => 50),
);