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HomeBackend DevelopmentPHP Tutorial问一个逻辑运算算法的思路



大概意思就是a是b的父级,b是c的父级,以此类推,无限顺延分级;
其中每一个成员都有一个对应的value值,这个value值为是1-30的随机数;
目前需要计算出,当我随意选择一个成员时,可以计算出这个成员以及向上所有的父级成员累计的value值总和是在哪一个成员身上value总值突破200的。


回复讨论(解决方案)

举个栗子,假如f的下一个成员是g,f是g的父级,g的value值为190,
那么最后计算出的结果就是在d这一父级的时候,g和g的所有父级的value值总在d这一级的时候总值达到了203,突破了200,那么d这个成员就是我最后要的结果。

求助!!!!!!!!!!!!!!

递归吧

//类里面的递归函数function test($id,$num=0,$max=200){        $sql="SELECT * FROM {{test}} WHERE id=$id";	$res=Yii::app()->db->createCommand($sql)->queryRow();	$num+=$res['value'];	if($num<$max){            $name=self::test($res['pid'],$num);	}else{            $name=$res['name'];        }	return $name;    }//调用$tr=new classtest();echo $tr->test(7);//结果 d

如果你的pid都比id小的话比较好办
order by pid desc 
然后循环fetch即可, 

给个奇葩的sql,(符合上面条件的情况下) 
select * from (
select id, pid, `value`, 
if(id=@p, concat(@p:=pid,'|',@a := @a+`value`), ''), if(@a>@s, id, '-') as Final,   @a
from test, (select @a:=0, @p:=6, @s:=30) x   -- 其中6改成你所选择的成员的id, 30 改成你的界(200)
where @a order by pid desc, id
) y
where Final!='-'
limit 1
;
当然实际上在php里计算比较方便。 


如果不满足这个条件的话。。。。好像只能反复查询了。。。。。。

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