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Re: ans2怎么推。。

Posted by wyh4104314 at 2008-08-31 18:02:00 on Problem 3682
In Reply To:Re:大牛们都怎么做的啊？提示一下吧～～～迭代算出概率过了但是好慢啊 Posted by:TheBeet at 2008-08-31 17:47:01 
> ans1 = k / p;
> ans2 = (k + 1) * ans1 / p - ans1;

ans2，
怎么来的，上面那个式子，
我是这样，
推ans2=k^2*p^k + (k+1)^2*C(k+1,1)*(1-p)*p^k +...
        + (k+i)^2*C(k+i-1,i)*(1-p)^i*p^k+...
然后迭代算ans2，tle！
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