2022-04-28：有 n 个城市通过一些航班连接。给你一个数组 flights ，其中 flights[i] = [from

fn main() {
    let n: isize = 3;
    let mut edges: Vec<Vec<isize>> = vec![vec![0, 1, 100], vec![1, 2, 100], vec![0, 2, 500]];
    let src: isize = 0;
    let dst: isize = 2;
    let k: isize = 1;
    let ans = find_cheapest_price2(n, &mut edges, src, dst, k);
    println!("ans = {}", ans);
}

fn find_cheapest_price2(
    n: isize,
    flights: &mut Vec<Vec<isize>>,
    src: isize,
    dst: isize,
    k: isize,
) -> isize {
    let mut cost: Vec<isize> = vec![];
    for _k in 0..n {
        cost.push(9223372036854775807);
    }
    cost[src as usize] = 0;
    for _i in 0..=k {
        let mut next: Vec<isize> = vec![];
        for j in 0..n {
            next.push(cost[j as usize]);
        }
        for j in 0..flights.len() {
            if cost[(flights[j as usize][0]) as usize] != 9223372036854775807 {
                next[(flights[j as usize][1]) as usize] = get_min(
                    next[(flights[j as usize][1]) as usize],
                    cost[(flights[j as usize][0]) as usize] + flights[j as usize][2],
                );
            }
        }
        cost = next;
    }
    if cost[dst as usize] == 9223372036854775807 {
        -1
    } else {
        cost[dst as usize]
    }
}

fn get_min(a: isize, b: isize) -> isize {
    if a < b {
        a
    } else {
        b
    }
}