結果
問題 | No.2712 Play more! |
ユーザー |
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提出日時 | 2024-03-31 15:11:38 |
言語 | Rust (1.83.0 + proconio) |
結果 |
AC
|
実行時間 | 406 ms / 2,000 ms |
コード長 | 3,468 bytes |
コンパイル時間 | 10,805 ms |
コンパイル使用メモリ | 377,844 KB |
実行使用メモリ | 5,248 KB |
最終ジャッジ日時 | 2024-09-30 23:49:33 |
合計ジャッジ時間 | 14,174 ms |
ジャッジサーバーID (参考情報) |
judge4 / judge5 |
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ファイルパターン | 結果 |
---|---|
sample | AC * 3 |
other | AC * 33 |
コンパイルメッセージ
warning: unused variable: `w` --> src/main.rs:99:21 | 99 | for &(u, v, w) in directed_edges.iter() { | ^ help: if this is intentional, prefix it with an underscore: `_w` | = note: `#[warn(unused_variables)]` on by default
ソースコード
#![allow(non_snake_case, unused_imports, unused_must_use)] use std::io::{self, prelude::*}; use std::str; fn main() { let (stdin, stdout) = (io::stdin(), io::stdout()); let mut scan = Scanner::new(stdin.lock()); let mut out = io::BufWriter::new(stdout.lock()); macro_rules! input { ($T: ty) => { scan.token::<$T>() }; ($T: ty, $N: expr) => { (0..$N).map(|_| scan.token::<$T>()).collect::<Vec<_>>() }; } let N = input!(usize); let M = input!(usize); let A = input!(isize, N); let mut edges = vec![]; for _ in 0..M { let a = input!(usize) - 1; let b = input!(usize) - 1; let c = input!(isize); edges.push((a, b, c - A[a])); } let ans = bellman_ford_algorithm(N, &edges, 0); if let Some(dist) = ans { writeln!(out, "{}", -dist[N - 1].unwrap() + A[N - 1]); } else { writeln!(out, "inf"); } } pub fn bellman_ford_algorithm< W: Sized + std::ops::Add<Output = W> + PartialOrd + Ord + Default + Clone + Copy, >( size: usize, directed_edges: &[(usize, usize, W)], start: usize, ) -> Option<Vec<Option<W>>> { assert!(start < size); let mut dist = vec![None; size]; dist[start] = Some(W::default()); for _ in 0..directed_edges.len() { for &(u, v, w) in directed_edges.iter() { let dv = dist[v]; let du = dist[u]; if let Some(du) = du { if let Some(dv) = dv { if dv > du + w { dist[v] = Some(du + w); } } else { dist[v] = Some(du + w); } } } } let dist_prev = dist.clone(); for _ in 0..directed_edges.len() { for &(u, v, w) in directed_edges.iter() { let dv = dist[v]; let du = dist[u]; if let Some(du) = du { if let Some(dv) = dv { if dv > du + w { dist[v] = Some(du + w); } } else { dist[v] = Some(du + w); } } } } let mut is_inf = vec![false; size]; for i in 0..size { if dist[i] != dist_prev[i] { is_inf[i] = true; } } for _ in 0..directed_edges.len() { for &(u, v, w) in directed_edges.iter() { if is_inf[u] { is_inf[v] = true; } } } if is_inf[size - 1] { return None; } Some(dist) } struct Scanner<R> { reader: R, buf_str: Vec<u8>, buf_iter: str::SplitWhitespace<'static>, } impl<R: BufRead> Scanner<R> { fn new(reader: R) -> Self { Self { reader, buf_str: vec![], buf_iter: "".split_whitespace(), } } fn token<T: str::FromStr>(&mut self) -> T { loop { if let Some(token) = self.buf_iter.next() { return token.parse().ok().expect("Failed parse"); } self.buf_str.clear(); self.reader .read_until(b'\n', &mut self.buf_str) .expect("Failed read"); self.buf_iter = unsafe { let slice = str::from_utf8_unchecked(&self.buf_str); std::mem::transmute(slice.split_whitespace()) } } } }