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大水题。只要找出所有经过的边，总和乘上2，然后减去一条到某个点距离最大的值，就是答案

Posted by yygy at 2012-11-10 00:19:16 on Problem 1935
In Reply To:经典树形DP Posted by:yc5_yc at 2012-11-09 21:59:25 
> 类似Apple Tree
> 方程：
> dp[a][0]=sum{dp[i][0]
>             +(2*dist{i,a}|i is in M or dp[i][0]!=0)}(i is a child of a)
> dp[a][1]=dp[a][0]
>         -max{dp[i][0]-dp[i][1]
>             +(dist{i,a}|i is in M or dp[i][0]!=0)}(i is a child of a)
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