結果

問題 No.1488 Max Score of the Tree
ユーザー fukafukatani
提出日時 2021-04-23 22:46:13
言語 Rust
(1.83.0 + proconio)
結果
AC  
実行時間 16 ms / 2,000 ms
コード長 2,186 bytes
コンパイル時間 13,590 ms
コンパイル使用メモリ 401,524 KB
実行使用メモリ 6,944 KB
最終ジャッジ日時 2024-07-04 08:28:44
合計ジャッジ時間 13,976 ms
ジャッジサーバーID
（参考情報） 		judge5 / 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 * 29
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(unused_imports)]
use std::cmp::*;
use std::collections::*;
use std::io::Write;
use std::ops::Bound::*;
#[allow(unused_macros)]
macro_rules! debug {
    ($($e:expr),*) => {
        #[cfg(debug_assertions)]
        $({
            let (e, mut err) = (stringify!($e), std::io::stderr());
            writeln!(err, "{} = {:?}", e, $e).unwrap()
        })*
    };
}
fn main() {
    let v = read_vec::<usize>();
    let (n, k) = (v[0], v[1]);
    let mut edges = vec![vec![]; n];
    let mut edges_list = HashMap::new();
    let mut weights = vec![];
    for i in 0..n - 1 {
        let v = read_vec::<usize>();
        let (a, b, c) = (v[0] - 1, v[1] - 1, v[2] as i64);
        edges[a].push(b);
        edges[b].push(a);
        edges_list.insert((a, b), i);
        edges_list.insert((b, a), i);
        weights.push(c);
    }
    let mut accum = vec![0; n - 1];
    dfs(0, 0, &edges, &edges_list, &mut accum);
    let mut dp = vec![-1; k + 1];
    dp[0] = 0;
    for i in 0..n - 1 {
        for prev in (0..k).rev() {
            let next = prev + weights[i] as usize;
            if next > k || dp[prev] == -1 {
                continue;
            }
            dp[next] = max(dp[next], dp[prev] + weights[i] * accum[i]);
        }
    }
    let ans = dp.iter().max().unwrap() + (0..n - 1).map(|i| weights[i] * accum[i]).sum::<i64>();
    println!("{}", ans);
}
fn dfs(
    cur: usize,
    parent: usize,
    edges: &Vec<Vec<usize>>,
    edges_list: &HashMap<(usize, usize), usize>,
    accum: &mut Vec<i64>,
) -> i64 {
    if edges[cur].iter().filter(|&&x| x != parent).count() == 0 {
        return 1;
    }
    let mut ret = 0;
    for &to in edges[cur].iter().filter(|&&x| x != parent) {
        let edge_index = edges_list[&(cur, to)];
        accum[edge_index] = dfs(to, cur, edges, edges_list, accum);
        ret += accum[edge_index];
    }
    ret
}
fn read<T: std::str::FromStr>() -> T {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    s.trim().parse().ok().unwrap()
}
fn read_vec<T: std::str::FromStr>() -> Vec<T> {
    read::<String>()
        .split_whitespace()
        .map(|e| e.parse().ok().unwrap())
        .collect()
}
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