大转盘中奖概率算法与示例





代码如下
header(“Content-type: text/html; charset=utf-8″);
$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),
);

$actor = 100;

foreach ($prize_arr as $v) {
$arr[$v[‘id’]] = $v[‘v’];
}
foreach ($arr as &$v) {
$v = $v*$actor;
}
asort($arr);
$sum = array_sum($arr); //总概率

$rand = mt_rand(1,$sum);

$result = ”; //中奖产品id

foreach ($arr as $k => $x)
{
if($rand <= $x)
{
$result = $k;
break;
}
else
{
$rand -= $x;
}
}
$res[‘yes’] = $prize_arr[$result-1][‘prize’]; //中奖项
print_r($res);