AtCoder Beginner Contest 410 D

https://atcoder.jp/contests/abc410/tasks/abc410_d

ノードが1000点までで重みも1023までなので、しらみつぶしができます。

// XOR Shortest Walk
#![allow(non_snake_case)]


//////////////////// library ////////////////////

fn read<T: std::str::FromStr>() -> T {
    let mut line = String::new();
    std::io::stdin().read_line(&mut line).ok();
    line.trim().parse().ok().unwrap()
}

fn read_vec<T: std::str::FromStr>() -> Vec<T> {
    read::<String>().split_whitespace()
            .map(|e| e.parse().ok().unwrap()).collect()
}


//////////////////// Graph ////////////////////

type Node = usize;
type Weight = usize;
type Edge = (Node, Node, Weight);

fn read_edge() -> Edge {
    let v: Vec<usize> = read_vec();
    (v[0] - 1, v[1] - 1, v[2])
}

struct Graph {
    g: Vec<Vec<(Node, Weight)>>
}

impl Graph {
    fn walk(&self, visited: &mut Vec<Vec<bool>>) {
        let mut stack: Vec<(Node, Weight)> = vec![(0, 0)];
        visited[0][0] = true;
        while let Some((v, w)) = stack.pop() {
            for &(v1, w1) in self.g[v].iter() {
                if !visited[v1][w^w1] {
                    visited[v1][w^w1] = true;
                    stack.push((v1, w^w1))
                }
            }
        }
    }
    
    fn create_from_edges(N: usize, edges: Vec<Edge>) -> Graph {
        let mut g: Vec<Vec<(Node, Weight)>> = vec![vec![]; N];
        for (A, B, W) in edges {
            g[A].push((B, W))
        }
        Graph { g }
    }
}


//////////////////// process ////////////////////

fn read_input() -> (usize, Vec<Edge>) {
    let v: Vec<usize> = read_vec();
    let (N, M) = (v[0], v[1]);
    let edges: Vec<Edge> = (0..M).map(|_| read_edge()).collect();
    (N, edges)
}

fn F(N: usize, edges: Vec<Edge>) -> i32 {
    let graph = Graph::create_from_edges(N, edges);
    let mut visited: Vec<Vec<bool>> = vec![vec![false; 1024]; N];
    graph.walk(&mut visited);
    if let Some(w) = (0..1024).filter(|&w| visited[N-1][w]).min() {
        w as i32
    }
    else {
        -1
    }
}

fn main() {
    let (N, edges) = read_input();
    println!("{}", F(N, edges))
}