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Parsa's Humongous Tree

1000ms 262144K

Description:

Parsa has a humongous tree on $$$n$$$ vertices.

On each vertex $$$v$$$ he has written two integers $$$l_v$$$ and $$$r_v$$$.

To make Parsa's tree look even more majestic, Nima wants to assign a number $$$a_v$$$ ($$$l_v \le a_v \le r_v$$$) to each vertex $$$v$$$ such that the beauty of Parsa's tree is maximized.

Nima's sense of the beauty is rather bizarre. He defines the beauty of the tree as the sum of $$$|a_u - a_v|$$$ over all edges $$$(u, v)$$$ of the tree.

Since Parsa's tree is too large, Nima can't maximize its beauty on his own. Your task is to find the maximum possible beauty for Parsa's tree.

Input:

The first line contains an integer $$$t$$$ $$$(1\le t\le 250)$$$ — the number of test cases. The description of the test cases follows.

The first line of each test case contains a single integer $$$n$$$ $$$(2\le n\le 10^5)$$$ — the number of vertices in Parsa's tree.

The $$$i$$$-th of the following $$$n$$$ lines contains two integers $$$l_i$$$ and $$$r_i$$$ $$$(1 \le l_i \le r_i \le 10^9)$$$.

Each of the next $$$n-1$$$ lines contains two integers $$$u$$$ and $$$v$$$ $$$(1 \le u , v \le n, u\neq v)$$$ meaning that there is an edge between the vertices $$$u$$$ and $$$v$$$ in Parsa's tree.

It is guaranteed that the given graph is a tree.

It is guaranteed that the sum of $$$n$$$ over all test cases doesn't exceed $$$2 \cdot 10^5$$$.

Output:

For each test case print the maximum possible beauty for Parsa's tree.

Sample Input:

3
2
1 6
3 8
1 2
3
1 3
4 6
7 9
1 2
2 3
6
3 14
12 20
12 19
2 12
10 17
3 17
3 2
6 5
1 5
2 6
4 6

Sample Output:

7
8
62

Note:

The trees in the example:

In the first test case, one possible assignment is $$$a = \{1, 8\}$$$ which results in $$$|1 - 8| = 7$$$.

In the second test case, one of the possible assignments is $$$a = \{1, 5, 9\}$$$ which results in a beauty of $$$|1 - 5| + |5 - 9| = 8$$$

Informação

Codeforces

Provedor Codeforces

Código CF1528A

Tags

dfs and similardivide and conquerdpgreedytrees

Submetido 0

BOUA! 0

Taxa de BOUA's 0%

Datas 09/05/2023 10:14:26

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