php中的随机加权硬币翻转答案

【问题标题】：Random weighted coin flip in phpphp中的随机加权硬币翻转
【发布时间】：2020-01-21 21:36:16
【问题描述】：

我正在尝试在 php 中创建一个抛硬币算法，该算法根据抛硬币的赌注金额进行加权。

例如，我希望下注较高的用户获胜的机会较低。下注 1 是 50/50 的机会，但任何事情都会慢慢变得越来越不可能获胜。

我已经搞砸了很多，似乎真的无法将硬币翻转编码为这种行为。

这是一个没有 IRL 值的积分余额系统，仅用于我托管的游戏服务器。使用当前系统，用户可以通过自动点击器轻松增加他们的余额，因为它是双翻转或无翻转。

这是我现在正在尝试的，但效果不是很好

<?PHP
$choices = ["heads", "tails","tails", "heads","heads", "tails","heads", "tails", "heads"];
$result = $choices[random_int(0, count($choices)-1)];
$wager = $_GET['wager'];
$win = $wager *2;

if (!is_numeric($wager)) {
    die("You must enter a number for your wager.");
}

if ($wager > $usrdata['money']) {
    die("You don't have enough credits to make this bet.");
}

if ($result  == "tails") {
    if ($_GET['side'] == 0) {
        $newrand = rand(0, $wager);
    }
    $newrandx = rand(0, 1);
    if ($newrandx == 1 && $side == 0) {
        echo '<img src="https://static.pdglobal.app/?sid=files_go&ID=HEADS" />';
    $side = 1;
    } else {
    if ($wager/2 >= $newrand) {
    echo '<img src="https://static.pdglobal.app/?sid=files_go&ID=TAILS" />';
    $side = 0;
    } else {
        echo '<img src="https://static.pdglobal.app/?sid=files_go&ID=HEADS" />';
    $side = 1;

    }
    }
} else {

    if ($_GET['side'] == 1) {
        $newrand = rand(0, $wager);
    }
        $newrandx = rand(0, 1);
    if ($newrandx == 1 && $side == 1) {
        echo '<img src="https://static.pdglobal.app/?sid=files_go&ID=TAILS" />';
    $side = 0;
    } else {
    if ($newrand >= $wager/2) {
    echo '<img src="https://static.pdglobal.app/?sid=files_go&ID=HEADS" />';
    $side = 1;
    } else {
    echo '<img src="https://static.pdglobal.app/?sid=files_go&ID=TAILS" />';
    $side = 0;  

    }
    }
}

if ($side == $_GET['side']) {
    echo '<br/> You won '.$win.' credits!';
    $total = $usrdata['money'] + $win;
    mysql_query("UPDATE account SET money = '".$total."' WHERE username = '".$usrdata['username']."';") or die(mysql_error());
} else {
    echo '<br/> You lost '.$wager.' credits!';
    $total = $usrdata['money'] - $wager;
    mysql_query("UPDATE account SET money = '".$total."' WHERE username = '".$usrdata['username']."';") or die(mysql_error());
    }
?>

结果应该是较高赌注获胜的机会较低，但是，即使使用我编写的代码，它似乎仍然是准确的 50/50 机会。

【问题讨论】：

要对抛硬币进行加权，请从 0 到 99 中选择一个数字，并测试该数字是大于还是小于加权百分比。
那么您只需要决定如何将投注金额转换为百分比即可。

标签： php random flip weighted

【解决方案1】：

这似乎满足我的需要

<?PHP
$wager = $_GET['wager'];
$win = $wager *2;

if ($wager < 10) {
    die("You must wager at least 10 credits."); 
}

if ($_GET['side'] == 0) {
$values[0] = 0;
$weights[0] = 5;    
$values[1] = 1;
$weights[1] = $wager*2; 
} else {
    $values[0] = 0;
$weights[0] = $wager*2; 
$values[1] = 1;
$weights[1] = 5;    

}

$side = weighted_random_simple($values, $weights);


if (!is_numeric($wager)) {
    die("You must enter a number for your wager.");
}

if ($wager > $usrdata['money']) {
    die("You don't have enough credits to make this bet.");
}

if ($side  == 0) {
    echo '<img src="https://static.pdglobal.app/?sid=files_go&ID=TAILS" />';
} else {
echo '<img src="https://static.pdglobal.app/?sid=files_go&ID=HEADS" />';
}

if ($side == $_GET['side']) {
    echo '<br/> You won '.$win.' credits!';
    $total = $usrdata['money'] + $win;
    mysql_query("UPDATE account SET money = '".$total."' WHERE username = '".$usrdata['username']."';") or die(mysql_error());
} else {
    echo '<br/> You lost '.$wager.' credits!';
    $total = $usrdata['money'] - $wager;
    mysql_query("UPDATE account SET money = '".$total."' WHERE username = '".$usrdata['username']."';") or die(mysql_error());
    }

    function weighted_random_simple($values, $weights){ 
    $count = count($values); 
    $i = 0; 
    $n = 0; 
    $num = mt_rand(1, array_sum($weights)); 
    while($i < $count){
        $n += $weights[$i]; 
        if($n >= $num){
            break; 
        }
        $i++; 
    } 
    return $values[$i]; 
}
?>

【讨论】：