php砍价算法

/**
 * 砍价算法-生成砍价金额
 *
 * @author 宋健安<506780989@qq.com>
 *
 * @param int $people   砍价人数或次数
 * @param int $amount   砍价总额
 * @param int $min      最低砍价金额 不得低于0
 * @param int $max      最高砍价金额 砍价次数 * 最高砍价金额不得小于砍价总额
 * @param int $level    层级 防止递归超出限制
 *
 * @return array
 */
function genRandomAmount($people = 0, $totalAmount = 0, $min = 0, $max = 0, $level = 1)
{
    // 防止递归超出限制报异常，提前退出
    if ($level == 200) {
        return [];
    }

    $arr = [];

    if (empty($people) || empty($totalAmount)) {
        return [];
    }

    $tmpTotal = $totalAmount * 100;
    $tmpMin = $min * 100;
    $tmpMax = $max * 100;

    for ($i = 0; $i < $people - 1; $i++) {
        $arr[$i] = mt_rand($tmpMin, $tmpMax);
        $tmpTotal = $tmpTotal - $arr[$i];
    }

    $arr[$people - 1] = $tmpTotal;

    if ($tmpTotal < $tmpMin || $tmpTotal > $tmpMax) {
        return genRandomAmount($people, $totalAmount, $min, $max, $level + 1);
    }

    return array_map(function ($value) {
        return $value / 100;
    }, $arr);
}

/**
 * 砍价算法-获取砍价金额
 *
 * @author 宋健安<506780989@qq.com>
 *
 * @param int $people   砍价人数或次数
 * @param int $amount   砍价总额
 * @param int $min      最低砍价金额 不得低于0
 * @param int $max      最高砍价金额 砍价次数 * 最高砍价金额不得小于砍价总额
 *
 * @return array
 */
function getRandomAmount($people = 0, $totalAmount = 0, $min = 0, $max = 0)
{
    if ($people * $max <= $totalAmount) {
        return false;
    }
    $arr = genRandomAmount($people, $totalAmount, $min, $max);

    // 有几率会因为递归调用超出限制而返回空数组，这里继续重新生成，直到金额正确
    while (empty($arr)) {
        $arr = genRandomAmount($people, $totalAmount, $min, $max);
    }

    return $arr;
}