随意写的

protected function winner($arr){
    if(is_array($arr)){
        if(count($arr)<4){
            return 0;
        }else{
            foreach($arr as $key1=>$value1){
                foreach($arr as $key2=>$value2){
                    foreach($arr as $key3=>$value3){
                        if($key1!=$key2&&$key1!=$key3&&$key2!=$key3){
                            $all[]=$value1+$value2+$value3;
                        }
                    }
                }
            }
            $smart=array_intersect($all,$arr);
            if(empty($smart)){
                return 0;
            }else{
                rsort($smart);
                return $smart[0];
            }
        }
    }else{
        return 0;
    }
}

/**
 * @param $n 取几个数之和
 * @param $arr 传入数组
 * @param int $total 
 * @return array
 */
protected function aller($n,$arr,$total=0){
    if($n==1){
        $all=array();
        foreach($arr as $key=>$value){
            $all[]=$total+$value;
        }
        return $all;
    }else{
        $alls=array();
        $arrer=$arr;
        foreach($arr as $key=>$value){
            unset($arrer[$key]);
            $alls=array_merge($alls,self::aller($n-1,$arrer,$value+$total));
        }
        return $alls;
    }
}

 素数和素数对

protected function twoprimenumber($n){
    if(is_numeric($n)){
        $k=0;
        for($s=1;$s<=$n;$s++){
            if(self::primenumber($s)&&self::primenumber($s-2)){
                $k++;
            }
        }
        return $k;
    }else{
        return 0;
    }
}

protected function primenumber($n){
    if(is_numeric($n)){
        if($n>1){
            $k=0;
            for($s=1;$s<=$n;$s++){
                if($n%$s==0){
                    $k++;
                }
            }
            return $k==2?1:0;
        }else{
            return 0;
        }
    }else{
        return 0;
    }
}
一只鸡5天三个蛋，3天后蛋变鸡，33天鸡死亡，算法

<?php
class Mtceshi{
    public function index(){
        self::number(100,1);
    }

    /**
     * @param $days 时间
     * @param $number 开始数量
     */
    protected function number($days,$number){
        $all=array(array('egg'=>0,'chicken'=>$number));
        for($i=0;$i<=$days;$i++){
            if($all[$i-3]['egg']){
                $all[$i]['chicken']=$all[$i-3]['egg'];
                $all[$i-3]['egg']=0;
            }
            if($all[$i-33]['chicken']){
                $all[$i-33]['chicken']=0;
            }
            for($m=6;$m>=1;$m--){
                if($all[$i-5*$m]['chicken']){
                    for($n=1;$n<=$m;$n++){
                        $all[$i]['egg']=$all[$i]['egg']+$all[$i-5*$n]['chicken']*3;
                    }
                    break;
                }
            }
        }
        $egg=0;
        $chicken=0;
        foreach($all as $key=>$value){
            $egg+=$value['egg'];
            $chicken+=$value['chicken'];
        }
        print_r($egg."--"."$chicken");
    }
}