AtCoder Beginner Contest 325 E

https://atcoder.jp/contests/abc325/tasks/abc325_e

ダイクストラ法ですが、社用車と電車の2つのテーブルが必要です。

// Our clients, please wait a moment
#![allow(non_snake_case)]

use std::cmp::min;
use std::collections::BinaryHeap;


//////////////////// 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()
}


//////////////////// Item ////////////////////

#[derive(PartialEq, Eq, Clone)]
enum Transportation {
    Car, Train
}

type City = usize;

#[derive(Clone, Eq, PartialEq)]
struct Item(City, u64, Transportation);

impl Ord for Item {
    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
        other.1.cmp(&self.1)
    }
}

impl PartialOrd for Item {
    fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
        Some(self.cmp(other))
    }
}


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

fn read_input() -> (u64, u64, u64, Vec<Vec<u64>>) {
    let v = read_vec();
    let (N, A, B, C) = (v[0], v[1], v[2], v[3]);
    let D: Vec<Vec<u64>> = (0..N).map(|_| read_vec::<u64>()).collect();
    (A, B, C, D)
}

fn F(A: u64, B: u64, C: u64, D: Vec<Vec<u64>>) -> u64 {
    let N = D.len();
    let mut car_times: Vec<Option<u64>> = vec![None; N];
    let mut train_times: Vec<Option<u64>> = vec![None; N];
    let mut heap = BinaryHeap::new();
    heap.push(Item(0, 0, Transportation::Car));
    while let Some(item) = heap.pop() {
        let (city, time, trans) = (item.0, item.1, item.2);
        if trans == Transportation::Car {
            match car_times[city] {
                None => car_times[city] = Some(time),
                _    => continue
            }
        }
        if trans == Transportation::Train {
            match train_times[city] {
                None => train_times[city] = Some(time),
                _    => continue
            }
        }
        
        for neighbor in (0..N).filter(|&c| c != city) {
            if trans == Transportation::Car && car_times[neighbor].is_none() {
                let t = time + D[city][neighbor] * A;
                heap.push(Item(neighbor, t, Transportation::Car))
            }
            if train_times[neighbor].is_none() {
                let t = time + D[city][neighbor] * B + C;
                heap.push(Item(neighbor, t, Transportation::Train))
            }
        }
    }
    min(car_times[N-1].unwrap(), train_times[N-1].unwrap())
}

fn main() {
    let (A, B, C, D) = read_input();
    println!("{}", F(A, B, C, D))
}