AtCoder Beginner Contest 133
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Problem Statement
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There is a tree with $N$ vertices numbered $1$ to $N$. The $i$-th edge in this tree connects Vertex $a_i$ and Vertex $b_i$, and the color and length of that edge are $c_i$ and $d_i$, respectively. Here the color of each edge is represented by an integer between $1$ and $N-1$ (inclusive). The same integer corresponds to the same color, and different integers correspond to different colors.
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Answer the following $Q$ queries:
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- Query
$j$($1 \leq j \leq Q$): assuming that the length of every edge whose color is$x_j$is changed to$y_j$, find the distance between Vertex$u_j$and Vertex$v_j$. (The changes of the lengths of edges do not affect the subsequent queries.)
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Constraints
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$2 \leq N \leq 10^5$$1 \leq Q \leq 10^5$$1 \leq a_i, b_i \leq N$$1 \leq c_i \leq N-1$$1 \leq d_i \leq 10^4$$1 \leq x_j \leq N-1$$1 \leq y_j \leq 10^4$$1 \leq u_j < v_j \leq N$- The given graph is a tree.
- All values in input are integers.
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Input
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Input is given from Standard Input in the following format:
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N Q
a_1 b_1 c_1 d_1
:
a_{N-1} b_{N-1} c_{N-1} d_{N-1}
x_1 y_1 u_1 v_1
:
x_Q y_Q u_Q v_Q
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Output
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Print $Q$ lines. The $j$-th line ($1 \leq j \leq Q$) should contain the answer to Query $j$.
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样例
Input #1
5 3
1 2 1 10
1 3 2 20
2 4 4 30
5 2 1 40
1 100 1 4
1 100 1 5
3 1000 3 4
Output #1
130
200
60
The graph in this input is as follows:

Here the edges of Color $1$ are shown as solid red lines, the edge of Color $2$ is shown as a bold green line, and the edge of Color $4$ is shown as a blue dashed line.
- Query $1$: Assuming that the length of every edge whose color is $1$ is changed to $100$, the distance between Vertex $1$ and Vertex $4$ is $100 + 30 = 130$.
- Query $2$: Assuming that the length of every edge whose color is $1$ is changed to $100$, the distance between Vertex $1$ and Vertex $5$ is $100 + 100 = 200$.
- Query $3$: Assuming that the length of every edge whose color is $3$ is changed to $1000$ (there is no such edge), the distance between Vertex $3$ and Vertex $4$ is $20 + 10 + 30 = 60$. Note that the edges of Color $1$ now have their original lengths.
题目信息
题面与样例版权归 AtCoder 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。