use std::cmp::*; // 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, usize1) => (read_value!($next, usize) - 1); ($next:expr, $t:ty) => ($next().parse::<$t>().expect("Parse error")); } /* * Dijkstra's algorithm. * Verified by: AtCoder ABC164 (https://atcoder.jp/contests/abc164/submissions/12423853) */ struct Dijkstra { edges: Vec>, // adjacent list representation } impl Dijkstra { fn new(n: usize) -> Self { Dijkstra { edges: vec![Vec::new(); n] } } fn add_edge(&mut self, from: usize, to: usize, cost: i64) { self.edges[from].push((to, cost)); } /* * This function returns a Vec consisting of the distances from vertex source. */ fn solve(&self, source: usize, inf: i64) -> Vec { let n = self.edges.len(); let mut d = vec![inf; n]; // que holds (-distance, vertex), so that que.pop() returns the nearest element. let mut que = std::collections::BinaryHeap::new(); que.push((0, source)); while let Some((cost, pos)) = que.pop() { let cost = -cost; if d[pos] <= cost { continue; } d[pos] = cost; for &(w, c) in &self.edges[pos] { let newcost = cost + c; if d[w] > newcost { d[w] = newcost + 1; que.push((-newcost, w)); } } } return d; } } fn main() { input! { n: usize, m: usize, k: usize, r: [usize1; k], abc: [(usize1, usize1, i64); m], } let mut dijk = Dijkstra::new(n); for &(a, b, c) in &abc { dijk.add_edge(a, b, c); dijk.add_edge(b, a, c); } const INF: i64 = 1 << 50; let s0 = dijk.solve(0, INF); let s1 = dijk.solve(n - 1, INF); let mut s = vec![vec![]; 2 * k]; let mut v = vec![0; 2 * k]; for i in 0..k { let (a, b, _) = abc[r[i]]; s[2 * i] = dijk.solve(a, INF); s[2 * i + 1] = dijk.solve(b, INF); v[2 * i] = a; v[2 * i + 1] = b; } let mut dp = vec![vec![INF; 1 << k]; 2 * k]; for i in 0..2 * k { dp[i ^ 1][1 << (i / 2)] = s0[v[i]]; } for bits in 1..1 << k { for j in 0..2 * k { if (bits & 1 << (j / 2)) == 0 { continue; } let pre = bits ^ 1 << (j / 2); for l in 0..2 * k { dp[l][bits] = min(dp[l][bits], dp[j][pre] + s[j][v[l] ^ 1]); } } } let mut ans = INF; for j in 0..2 * k { ans = min(ans, dp[j][(1 << n) - 1] + s1[v[j]]); } println!("{}", ans); }