CleverCode最近接到一个需求,需要写一个固定红包 + 随机红包算法。
1 固定红包就是每个红包金额一样,有多少个就发多少个固定红包金额就行。
2 随机红包的需求是。比如红包总金额5元,需要发10个红包。随机范围是 0.01到0.99;5元必需发完,金额需要有一定趋势的正态分布。(0.99可以任意指定,也可以是 avg * 2 - 0.01;比如avg = 5 / 10 = 0.5;(avg * 2 - 0.01 = 0.99))
如果是固定红包,则算法是一条直线。t就是固定红包的额度。如图。
f(x) = t;(1 813a03ef8e1815512061e3f8604b4efe totalMoney ,说明生成金额多了,需要修数据,则从(y1,y2,y3.....ynum)这些每次减少0.01。直到y(合) = totalMoney。
y(合)有可能 < totalMoney ,说明生成金额少了,需要修数据,则从(y1,y2,y3.....ynum)这些每次加上0.01。直到y(合) = totalMoney。
2 算法原理样例
如果需要发红包总金额是11470,红包个数是7400个,金额范围是[0.01,3.09],线性方程如图。
<?php /** * 随机红包+固定红包算法[策略模式] * copyright (c) 2016 http://blog.csdn.net/CleverCode */ //配置传输数据DTO class OptionDTO {/*{{{*/ //红包总金额 public $totalMoney; //红包数量 public $num; //范围开始 public $rangeStart; //范围结算 public $rangeEnd; //生成红包策略 public $builderStrategy; //随机红包剩余规则 public $randFormatType; //Can_Left:不修数据,可以有剩余;No_Left:不能有剩余 public static function create($totalMoney,$num,$rangeStart,$rangEnd, $builderStrategy,$randFormatType = 'No_Left') {/*{{{*/ $self = new self(); $self->num = $num; $self->rangeStart = $rangeStart; $self->rangeEnd = $rangEnd; $self->totalMoney = $totalMoney; $self->builderStrategy = $builderStrategy; $self->randFormatType = $randFormatType; return $self; }/*}}}*/ }/*}}}*/ //红包生成器接口 interface IBuilderStrategy {/*{{{*/ //创建红包 public function create(); //设置配置 public function setOption(OptionDTO $option); //是否可以生成红包 public function isCanBuilder(); //生成红包函数 public function fx($x); }/*}}}*/ //固定等额红包策略 class EqualPackageStrategy implements IBuilderStrategy {/*{{{*/ //单个红包金额 public $oneMoney; //数量 public $num; public function construct($option = null) { if($option instanceof OptionDTO) { $this->setOption($option); } } public function setOption(OptionDTO $option) { $this->oneMoney = $option->rangeStart; $this->num = $option->num; } public function create() {/*{{{*/ $data = array(); if(false == $this->isCanBuilder()) { return $data; } $data = array(); if(false == is_int($this->num) || $this->num <= 0) { return $data; } for($i = 1;$i <= $this->num;$i++) { $data[$i] = $this->fx($i); } return $data; }/*}}}*/ /** * 等额红包的方程是一条直线 * * @param mixed $x * @access public * @return void */ public function fx($x) {/*{{{*/ return $this->oneMoney; }/*}}}*/ /** * 是否能固定红包 * * @access public * @return void */ public function isCanBuilder() {/*{{{*/ if(false == is_int($this->num) || $this->num <= 0) { return false; } if(false == is_numeric($this->oneMoney) || $this->oneMoney <= 0) { return false; } //单个红包小于1分 if($this->oneMoney < 0.01) { return false; } return true; }/*}}}*/ }/*}}}*/ //随机红包策略(三角形) class RandTrianglePackageStrategy implements IBuilderStrategy {/*{{{*/ //总额 public $totalMoney; //红包数量 public $num; //随机红包最小值 public $minMoney; //随机红包最大值 public $maxMoney; //修数据方式:NO_LEFT: 红包总额 = 预算总额;CAN_LEFT: 红包总额 <= 预算总额 public $formatType; //预算剩余金额 public $leftMoney; public function construct($option = null) {/*{{{*/ if($option instanceof OptionDTO) { $this->setOption($option); } }/*}}}*/ public function setOption(OptionDTO $option) {/*{{{*/ $this->totalMoney = $option->totalMoney; $this->num = $option->num; $this->formatType = $option->randFormatType; $this->minMoney = $option->rangeStart; $this->maxMoney = $option->rangeEnd; $this->leftMoney = $this->totalMoney; }/*}}}*/ /** * 创建随机红包 * * @access public * @return void */ public function create() {/*{{{*/ $data = array(); if(false == $this->isCanBuilder()) { return $data; } $leftMoney = $this->leftMoney; for($i = 1;$i <= $this->num;$i++) { $data[$i] = $this->fx($i); $leftMoney = $leftMoney - $data[$i]; } //修数据 list($okLeftMoney,$okData) = $this->format($leftMoney,$data); //随机排序 shuffle($okData); $this->leftMoney = $okLeftMoney; return $okData; }/*}}}*/ /** * 是否能够发随机红包 * * @access public * @return void */ public function isCanBuilder() {/*{{{*/ if(false == is_int($this->num) || $this->num <= 0) { return false; } if(false == is_numeric($this->totalMoney) || $this->totalMoney <= 0) { return false; } //均值 $avgMoney = $this->totalMoney / 1.0 / $this->num; //均值小于最小值 if($avgMoney < $this->minMoney ) { return false; } return true; }/*}}}*/ /** * 获取剩余金额 * * @access public * @return void */ public function getLeftMoney() {/*{{{*/ return $this->leftMoney; }/*}}}*/ /** * 随机红包生成函数。三角函数。[(1,0.01),($num/2,$avgMoney),($num,0.01)] * * @param mixed $x,1 <= $x <= $this->num; * @access public * @return void */ public function fx($x) {/*{{{*/ if(false == $this->isCanBuilder()) { return 0; } if($x < 1 || $x > $this->num) { return 0; } $x1 = 1; $y1 = $this->minMoney; //我的峰值 $y2 = $this->maxMoney; //中间点 $x2 = ceil($this->num / 1.0 / 2); //最后点 $x3 = $this->num; $y3 = $this->minMoney; //当x1,x2,x3都是1的时候(竖线) if($x1 == $x2 && $x2 == $x3) { return $y2; } // '/_\'三角形状的线性方程 //'/'部分 if($x1 != $x2 && $x >= $x1 && $x <= $x2) { $y = 1.0 * ($x - $x1) / ($x2 - $x1) * ($y2 - $y1) + $y1; return number_format($y, 2, '.', ''); } //'\'形状 if($x2 != $x3 && $x >= $x2 && $x <= $x3) { $y = 1.0 * ($x - $x2) / ($x3 - $x2) * ($y3 - $y2) + $y2; return number_format($y, 2, '.', ''); } return 0; }/*}}}*/ /** * 格式化修红包数据 * * @param mixed $leftMoney * @param array $data * @access public * @return void */ private function format($leftMoney,array $data) {/*{{{*/ //不能发随机红包 if(false == $this->isCanBuilder()) { return array($leftMoney,$data); } //红包剩余是0 if(0 == $leftMoney) { return array($leftMoney,$data); } //数组为空 if(count($data) < 1) { return array($leftMoney,$data); } //如果是可以有剩余,并且$leftMoney > 0 if('Can_Left' == $this->formatType && $leftMoney > 0) { return array($leftMoney,$data); } //我的峰值 $myMax = $this->maxMoney; // 如果还有余钱,则尝试加到小红包里,如果加不进去,则尝试下一个。 while($leftMoney > 0) { $found = 0; foreach($data as $key => $val) { //减少循环优化 if($leftMoney <= 0) { break; } //预判 $afterLeftMoney = (double)$leftMoney - 0.01; $afterVal = (double)$val + 0.01; if( $afterLeftMoney >= 0 && $afterVal <= $myMax) { $found = 1; $data[$key] = number_format($afterVal,2,'.',''); $leftMoney = $afterLeftMoney; //精度 $leftMoney = number_format($leftMoney,2,'.',''); } } //如果没有可以加的红包,需要结束,否则死循环 if($found == 0) { break; } } //如果$leftMoney < 0 ,说明生成的红包超过预算了,需要减少部分红包金额 while($leftMoney < 0) { $found = 0; foreach($data as $key => $val) { if($leftMoney >= 0) { break; } //预判 $afterLeftMoney = (double)$leftMoney + 0.01; $afterVal = (double)$val - 0.01; if( $afterLeftMoney <= 0 && $afterVal >= $this->minMoney) { $found = 1; $data[$key] = number_format($afterVal,2,'.',''); $leftMoney = $afterLeftMoney; $leftMoney = number_format($leftMoney,2,'.',''); } } //如果一个减少的红包都没有的话,需要结束,否则死循环 if($found == 0) { break; } } return array($leftMoney,$data); }/*}}}*/ }/*}}}*/ //维护策略的环境类 class RedPackageBuilder {/*{{{*/ // 实例 protected static $_instance = null; /** * Singleton instance(获取自己的实例) * * @return MemcacheOperate */ public static function getInstance() { /*{{{*/ if (null === self::$_instance) { self::$_instance = new self(); } return self::$_instance; } /*}}}*/ /** * 获取策略【使用反射】 * * @param string $type 类型 * @return void */ public function getBuilderStrategy($type) { /*{{{*/ $class = $type.'PackageStrategy'; if(class_exists($class)) { return new $class(); } else { throw new Exception("{$class} 类不存在!"); } } /*}}}*/ public function getRedPackageByDTO(OptionDTO $optionDTO) {/*{{{*/ //获取策略 $builderStrategy = $this->getBuilderStrategy($optionDTO->builderStrategy); //设置参数 $builderStrategy->setOption($optionDTO); return $builderStrategy->create(); }/*}}}*/ }/*}}}*/ class Client {/*{{{*/ public static function main($argv) { //固定红包 $dto = OptionDTO::create(1000,10,100,100,'Equal'); $data = RedPackageBuilder::getInstance()->getRedPackageByDTO($dto); //print_r($data); //随机红包[修数据] $dto = OptionDTO::create(5,10,0.01,0.99,'RandTriangle'); $data = RedPackageBuilder::getInstance()->getRedPackageByDTO($dto); print_r($data); //随机红包[不修数据] $dto = OptionDTO::create(5,10,0.01,0.99,'RandTriangle','Can_Left'); $data = RedPackageBuilder::getInstance()->getRedPackageByDTO($dto); //print_r($data); } }/*}}}*/ Client::main($argv);
1 固定红包
//固定红包 $dto = OptionDTO::create(1000,10,100,100,'Equal'); $data = RedPackageBuilder::getInstance()->getRedPackageByDTO($dto); print_r($data);
2 随机红包(修数据)
这里使用了php的随机排序函数, shuffle($okData),所以看到的结果不是线性的,这个结果更加随机性。
//随机红包[修数据] $dto = OptionDTO::create(5,10,0.01,0.99,'RandTriangle'); $data = RedPackageBuilder::getInstance()->getRedPackageByDTO($dto); print_r($data);
3 随机红包(不修数据)
不修数据,1 和num的金额是最小值0.01。
//随机红包[不修数据] $dto = OptionDTO::create(5,10,0.01,0.99,'RandTriangle','Can_Left'); $data = RedPackageBuilder::getInstance()->getRedPackageByDTO($dto); print_r($data);
以上是php如何实现固定红包以及随机红包算法详解(图)的详细内容。更多信息请关注PHP中文网其他相关文章!