use std::cmp::*; use std::collections::*; // https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8 macro_rules! input { ($($r:tt)*) => { let stdin = std::io::stdin(); let mut bytes = std::io::Read::bytes(std::io::BufReader::new(stdin.lock())); let mut next = move || -> String{ bytes.by_ref().map(|r|r.unwrap() as char) .skip_while(|c|c.is_whitespace()) .take_while(|c|!c.is_whitespace()) .collect() }; input_inner!{next, $($r)*} }; } macro_rules! input_inner { ($next:expr) => {}; ($next:expr,) => {}; ($next:expr, $var:ident : $t:tt $($r:tt)*) => { let $var = read_value!($next, $t); input_inner!{$next $($r)*} }; } macro_rules! read_value { ($next:expr, ( $($t:tt),* )) => { ($(read_value!($next, $t)),*) }; ($next:expr, [ $t:tt ; $len:expr ]) => { (0..$len).map(|_| read_value!($next, $t)).collect::>() }; ($next:expr, chars) => { read_value!($next, String).chars().collect::>() }; ($next:expr, usize1) => (read_value!($next, usize) - 1); ($next:expr, [ $t:tt ]) => {{ let len = read_value!($next, usize); read_value!($next, [$t; len]) }}; ($next:expr, $t:ty) => ($next().parse::<$t>().expect("Parse error")); } const INF: i64 = 1 << 50; fn main() { input! { t: i32, n: usize, m: usize, abc: [(usize1, usize1, i64); m], } let mut mi = INF; for i in 0..m { let mut g = vec![vec![]; n]; for j in 0..m { if i == j { continue; } let (a, b, c) = abc[j]; g[a].push((b, c)); if t == 0 { g[b].push((a, c)); } } let mut dist = vec![INF; n]; let mut que = BinaryHeap::new(); let (ai, bi, ci) = abc[i]; que.push((Reverse(0), bi)); while let Some((Reverse(d), v)) = que.pop() { if dist[v] <= d { continue; } dist[v] = d; for &(w, c) in &g[v] { que.push((Reverse(d + c), w)); } } mi = min(mi, dist[ai] + ci); } println!("{}", if mi >= INF { 0 } else { mi }); }