結果

問題 No.2638 Initial fare
ユーザー naut3
提出日時 2024-02-19 22:24:13
言語 Rust
(1.83.0 + proconio)
結果
AC  
実行時間 169 ms / 2,000 ms
コード長 2,732 bytes
コンパイル時間 13,737 ms
コンパイル使用メモリ 391,124 KB
実行使用メモリ 26,144 KB
最終ジャッジ日時 2024-09-29 02:17:53
合計ジャッジ時間 17,929 ms
ジャッジサーバーID
(参考情報)
judge1 / judge2
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 3
other AC * 25
権限があれば一括ダウンロードができます

ソースコード

diff #
プレゼンテーションモードにする

#![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 mut graph = vec![vec![]; N];
for _ in 0..N - 1 {
let (u, v) = (input!(usize) - 1, input!(usize) - 1);
graph[u].push(v);
graph[v].push(u);
}
let r = 0;
let mut dist = vec![0; N];
let mut seen = vec![false; N];
let mut q = std::collections::VecDeque::new();
q.push_back(r);
seen[r] = true;
while let Some(now) = q.pop_front() {
for &nxt in graph[now].iter() {
if seen[nxt] {
continue;
}
q.push_back(nxt);
dist[nxt] = dist[now] + 1;
seen[nxt] = true;
}
}
let mut ans = 0;
let mut dp1 = vec![0; N];
let mut dp2 = vec![0; N];
let mut dp3 = vec![0; N];
let mut order = (0..N).map(|i| i).collect::<Vec<_>>();
order.sort_by_key(|&i| dist[i]);
order.reverse();
for v in order {
if v != r {
dp1[v] = graph[v].len() - 1;
} else {
dp1[v] = graph[v].len();
}
for &nxt in graph[v].iter() {
if dist[nxt] <= dist[v] {
continue;
}
dp2[v] += dp1[nxt];
dp3[v] += dp2[nxt];
}
ans += dp1[v] + dp2[v] + dp3[v];
if dp1[v] != 0 {
ans += (dp1[v] - 1) * dp2[v] + (dp1[v] - 1) * dp1[v] / 2;
}
}
writeln!(out, "{}", ans);
}
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())
}
}
}
}
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