#[allow(unused_imports)] use std::cmp::*; #[allow(unused_imports)] use std::collections::*; use std::io::{Write, BufWriter}; // 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, [graph1; $len:expr]) => {{ let mut g = vec![vec![]; $len]; let ab = read_value!($next, [(usize1, usize1)]); for (a, b) in ab { g[a].push(b); g[b].push(a); } g }}; ($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::<$t>().expect("Parse error")); } #[allow(unused)] macro_rules! debug { ($($format:tt)*) => (write!(std::io::stderr(), $($format)*).unwrap()); } #[allow(unused)] macro_rules! debugln { ($($format:tt)*) => (writeln!(std::io::stderr(), $($format)*).unwrap()); } type Cap = isize; type Cost = i64; #[derive(Debug, Clone, Copy)] struct Edge { to: usize, cap: Cap, cost: Cost, rev: usize, // rev is the position of reverse edge in graph[to] } #[derive(Debug, Clone)] struct MinCostFlow { n: usize, graph: Vec>, h: Vec, // potential, dist: Vec, // minimum distance prev: Vec<(usize, usize)>, // previous vertex and edge } impl MinCostFlow { // Initializes this solver. n is the number of vertices. fn new(n: usize) -> Self { MinCostFlow { n: n, graph: vec![vec![]; n], h: vec![0; n], dist: vec![0; n], prev: vec![(0, 0); n], } } fn add_edge(&mut self, from: usize, to: usize, cap: Cap, cost: Cost) { let fst = Edge { to: to, cap: cap, cost: cost, rev: self.graph[to].len(), }; self.graph[from].push(fst); let snd = Edge { to: from, cap: 0, cost: -cost, rev: self.graph[from].len() - 1, }; self.graph[to].push(snd); } // Calcucates the minimum cost flow whose source is s, sink is t, and flow is f. fn min_cost_flow(&mut self, s: usize, t: usize, mut f: Cap) -> Cost { let n = self.n; let inf: Cost = Cost::MAX / 2; let mut res = 0; for i in 0..n { self.h[i] = 0; } let h = &mut self.h; let dist = &mut self.dist; while f > 0 { let mut que = std::collections::BinaryHeap::<(Cost, usize)>::new(); for i in 0..n { dist[i] = inf; } dist[s] = 0; que.push((0, s)); while let Some((d, v)) = que.pop() { let d = -d; if dist[v] < d { continue; } for (i, &e) in self.graph[v].iter().enumerate() { if e.cap > 0 && dist[e.to] > dist[v] + e.cost + h[v] - h[e.to] { dist[e.to] = dist[v] + e.cost + h[v] - h[e.to]; self.prev[e.to] = (v, i); que.push((-dist[e.to], e.to)); } } } if dist[t] == inf { return -1; // Cannot add flow anymore } for i in 0..n { h[i] += dist[i]; } // Add flow fully let mut d = f; let mut i = t; while i != s { let (pv, pe) = self.prev[i]; d = std::cmp::min(d, self.graph[pv][pe].cap); i = pv; } f -= d; res += d as Cost * h[t]; i = t; while i != s { let (pv, pe) = self.prev[i]; self.graph[pv][pe].cap -= d; let erev = self.graph[pv][pe].rev; self.graph[i][erev].cap += d; i = pv; } } return res; } } fn solve() { let out = std::io::stdout(); let mut out = BufWriter::new(out.lock()); macro_rules! puts { ($($format:tt)*) => (let _ = write!(out,$($format)*);); } #[allow(unused)] macro_rules! putvec { ($v:expr) => { for i in 0..$v.len() { puts!("{}{}", $v[i], if i + 1 == $v.len() {"\n"} else {" "}); } } } input! { n: usize, m: usize, uvcd: [(usize1, usize1, i64, i64); m], } let mut flow = MinCostFlow::new(n); for &(u, v, c, d) in &uvcd { flow.add_edge(u, v, 1, c); flow.add_edge(u, v, 1, d); flow.add_edge(v, u, 1, c); flow.add_edge(v, u, 1, d); } let ans = flow.min_cost_flow(0, n - 1, 2isize); puts!("{}\n", ans); } fn main() { // In order to avoid potential stack overflow, spawn a new thread. let stack_size = 104_857_600; // 100 MB let thd = std::thread::Builder::new().stack_size(stack_size); thd.spawn(|| solve()).unwrap().join().unwrap(); }