Problem:
Score : 600 points

Problem Statement

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.

Answer the following Q queries:

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.)

Constraints

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.

Input

Input is given from Standard Input in the following format:

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

Output

Print Q lines. The j-th line (1 \leq j \leq Q) should contain the answer to Query j.

Sample 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

Sample 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.

Solution in Rust (1.15.1) (judge verdict: Runtime Error)

pub struct Poper<'a> {
	iter: std::str::SplitWhitespace<'a>,
}

impl<'a> Poper<'a> {
	pub fn new(iter: std::str::SplitWhitespace) -> Poper {
		Poper { iter: iter }
	}
	pub fn read<T: std::str::FromStr>(&mut self) -> T
	where
		<T as std::str::FromStr>::Err: std::fmt::Debug,
	{
		self.iter.next().unwrap().parse().unwrap()
	}
}

fn main() {
	let input = {
		use std::io::Read;
		let mut s = String::new();
		std::io::stdin().read_to_string(&mut s).unwrap();
		s
	};
	let mut iter = Poper::new(input.split_whitespace());

	let n: usize = iter.read();
	let q: usize = iter.read();

	let tree = {
		let mut tree: Vec<Vec<Option<(usize, u64)>>> = vec![vec![None; n]; n];
		for _ in 1..n {
			let a: usize = iter.read::<usize>() - 1;
			let b: usize = iter.read::<usize>() - 1;
			let c: usize = iter.read::<usize>() - 1;
			let d: u64 = iter.read();
			tree[a][b] = Some((c, d));
			tree[b][a] = Some((c, d));
		}
		tree
	};

	for _ in 0..q {
		let c: usize = iter.read::<usize>() - 1;
		let d: u64 = iter.read();
		let u: usize = iter.read::<usize>() - 1;
		let v: usize = iter.read::<usize>() - 1;
		let r = run(&tree, v, u, n, c, d);
		println!("{}", r);
	}

	fn run(
		tree: &Vec<Vec<Option<(usize, u64)>>>,
		target: usize,
		current: usize,
		prev: usize,
		c2: usize,
		d2: u64,
	) -> u64 {
		for (t, &o) in tree[current].iter().enumerate() {
			if t == prev {
				continue;
			}
			match o {
				Some((c, d)) => {
					let d = if c == c2 { d2 } else { d };
					if t == target {
						return d;
					}
					let p = run(tree, target, t, current, c2, d2);
					if 0 < p {
						return d + p;
					}
				}
				None => continue,
			};
		}
		0
	}
}