Codeforces Round 525 (Div. 2) |
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Finished |
You're given a tree consisting of $$$n$$$ nodes. Every node $$$u$$$ has a weight $$$a_u$$$. It is guaranteed that there is only one node with minimum weight in the tree. For every node $$$u$$$ (except for the node with the minimum weight), it must have a neighbor $$$v$$$ such that $$$a_v<a_u$$$. You should construct a tree to minimize the weight $$$w$$$ calculated as follows:
The first line contains the integer $$$n$$$ $$$(2 \le n \le 5 \cdot 10^5)$$$, the number of nodes in the tree.
The second line contains $$$n$$$ space-separated integers $$$a_1, a_2, \ldots, a_n$$$ $$$(1 \le a_i \le 10^9)$$$, the weights of the nodes.
The next $$$n-1$$$ lines, each contains 2 space-separated integers $$$u$$$ and $$$v$$$ $$$(1 \le u,v \le n)$$$ which means there's an edge between $$$u$$$ and $$$v$$$.
Output one integer, the minimum possible value for $$$w$$$.
3
1 2 3
1 2
1 3
7
5
4 5 3 7 8
1 2
1 3
3 4
4 5
40
In the first sample, the tree itself minimizes the value of $$$w$$$.
In the second sample, the optimal tree is:
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